Merge pull request #627 from 0xProject/feature/contracts/erc721SafeTransferFrom

On-Chain AssetData Decoding Lib + safeTransferFrom for ERC721 + Memcpy

45 files changed, 1641 insertions, 429 deletions

diff --git a/packages/contracts/compiler.json b/packages/contracts/compiler.json
index 48ba4ffcd..6ef8e6a95 100644
--- a/packages/contracts/compiler.json
+++ b/packages/contracts/compiler.json
@@ -21,6 +21,7 @@
     "contracts": [
         "AssetProxyOwner",
         "DummyERC20Token",
+        "DummyERC721Receiver",
         "DummyERC721Token",
         "ERC20Proxy",
         "ERC721Proxy",
@@ -28,8 +29,10 @@
         "MixinAuthorizable",
         "MultiSigWallet",
         "MultiSigWalletWithTimeLock",
+        "TestAssetDataDecoders",
         "TestAssetProxyDispatcher",
         "TestLibBytes",
+        "TestLibMem",
         "TestLibs",
         "TestSignatureValidator",
         "TokenRegistry",
diff --git a/packages/contracts/package.json b/packages/contracts/package.json
index 99c507197..b533a22ce 100644
--- a/packages/contracts/package.json
+++ b/packages/contracts/package.json
@@ -30,7 +30,7 @@
         "test:circleci": "yarn test"
     },
     "config": {
-        "abis": "../migrations/artifacts/2.0.0/@(AssetProxyOwner|DummyERC20Token|DummyERC721Token|ERC20Proxy|ERC721Proxy|Exchange|MixinAuthorizable|MultiSigWallet|MultiSigWalletWithTimeLock|TestAssetProxyDispatcher|TestLibBytes|TestLibs|TestSignatureValidator|TokenRegistry|Whitelist|WETH9|ZRXToken).json"
+        "abis": "../migrations/artifacts/2.0.0/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|ERC20Proxy|ERC721Proxy|Exchange|MixinAuthorizable|MultiSigWallet|MultiSigWalletWithTimeLock|TestAssetDataDecoders|TestAssetProxyDispatcher|TestLibBytes|TestLibMem|TestLibs|TestSignatureValidator|TokenRegistry|Whitelist|WETH9|ZRXToken).json"
     },
     "repository": {
         "type": "git",
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol
index 2c321e134..dd25bf41a 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol
+++ b/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol
@@ -34,34 +34,30 @@ contract ERC20Proxy is
     uint8 constant PROXY_ID = 1;
 
     /// @dev Internal version of `transferFrom`.
-    /// @param assetMetadata Encoded byte array.
+    /// @param assetData Encoded byte array.
     /// @param from Address to transfer asset from.
     /// @param to Address to transfer asset to.
     /// @param amount Amount of asset to transfer.
     function transferFromInternal(
-        bytes memory assetMetadata,
+        bytes memory assetData,
         address from,
         address to,
         uint256 amount
     )
         internal
     {
-        // Data must be intended for this proxy.
-        uint256 length = assetMetadata.length;
+        // Decode asset data.
+        (
+            uint8 proxyId,
+            address token
+        ) = decodeERC20AssetData(assetData);
 
+        // Data must be intended for this proxy.
         require(
-            length == 21,
-            LENGTH_21_REQUIRED
-        );
-        // TODO: Is this too inflexible in the future?
-        require(
-            uint8(assetMetadata[length - 1]) == PROXY_ID,
+            proxyId == PROXY_ID,
             ASSET_PROXY_ID_MISMATCH
         );
 
-        // Decode metadata.
-        address token = readAddress(assetMetadata, 0);
-
         // Transfer tokens.
         bool success = IERC20Token(token).transferFrom(from, to, amount);
         require(
@@ -79,4 +75,30 @@ contract ERC20Proxy is
     {
         return PROXY_ID;
     }
+
+    /// @dev Decodes ERC20 Asset data.
+    /// @param assetData Encoded byte array.
+    /// @return proxyId Intended ERC20 proxy id.
+    /// @return token ERC20 token address.
+    function decodeERC20AssetData(bytes memory assetData)
+        internal
+        pure
+        returns (
+            uint8 proxyId,
+            address token
+        )
+    {
+        // Validate encoded data length
+        uint256 length = assetData.length;
+        require(
+            length == 21,
+            LENGTH_21_REQUIRED
+        );
+
+        // Decode data
+        token = readAddress(assetData, 0);
+        proxyId = uint8(assetData[length - 1]);
+
+        return (proxyId, token);
+    }
 }
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol
index 07e01c774..25136133d 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol
+++ b/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol
@@ -34,29 +34,30 @@ contract ERC721Proxy is
     uint8 constant PROXY_ID = 2;
 
     /// @dev Internal version of `transferFrom`.
-    /// @param assetMetadata Encoded byte array.
+    /// @param assetData Encoded byte array.
     /// @param from Address to transfer asset from.
     /// @param to Address to transfer asset to.
     /// @param amount Amount of asset to transfer.
     function transferFromInternal(
-        bytes memory assetMetadata,
+        bytes memory assetData,
         address from,
         address to,
         uint256 amount
     )
         internal
     {
-        // Data must be intended for this proxy.
-        uint256 length = assetMetadata.length;
+        // Decode asset data.
+        (
+            uint8 proxyId,
+            address token,
+            uint256 tokenId,
+            bytes memory receiverData
+        ) = decodeERC721AssetData(assetData);
 
-        require(
-            length == 53,
-            LENGTH_53_REQUIRED
-        );
 
-        // TODO: Is this too inflexible in the future?
+        // Data must be intended for this proxy.
         require(
-            uint8(assetMetadata[length - 1]) == PROXY_ID,
+            proxyId == PROXY_ID,
             ASSET_PROXY_ID_MISMATCH
         );
 
@@ -66,15 +67,13 @@ contract ERC721Proxy is
             INVALID_AMOUNT
         );
 
-        // Decode metadata
-        address token = readAddress(assetMetadata, 0);
-        uint256 tokenId = readUint256(assetMetadata, 20);
-
-        // Transfer token.
-        // Either succeeds or throws.
-        // @TODO: Call safeTransferFrom if there is additional
-        //        data stored in `assetMetadata`.
-        ERC721Token(token).transferFrom(from, to, tokenId);
+        // Transfer token. Saves gas by calling safeTransferFrom only
+        // when there is receiverData present. Either succeeds or throws.
+        if(receiverData.length > 0) {
+            ERC721Token(token).safeTransferFrom(from, to, tokenId, receiverData);
+        } else {
+            ERC721Token(token).transferFrom(from, to, tokenId);
+        }
     }
 
     /// @dev Gets the proxy id associated with the proxy address.
@@ -86,4 +85,44 @@ contract ERC721Proxy is
     {
         return PROXY_ID;
     }
+
+    /// @dev Decodes ERC721 Asset data.
+    /// @param assetData Encoded byte array.
+    /// @return proxyId Intended ERC721 proxy id.
+    /// @return token ERC721 token address.
+    /// @return tokenId ERC721 token id.
+    /// @return receiverData Additional data with no specific format, which
+    ///                      is passed to the receiving contract's onERC721Received.
+    function decodeERC721AssetData(bytes memory assetData)
+        internal
+        pure
+        returns (
+            uint8 proxyId,
+            address token,
+            uint256 tokenId,
+            bytes memory receiverData
+        )
+    {
+        // Validate encoded data length
+        uint256 length = assetData.length;
+        require(
+            length >= 53,
+            LENGTH_AT_LEAST_53_REQUIRED
+        );
+
+        // Decode asset data.
+        token = readAddress(assetData, 0);
+        tokenId = readUint256(assetData, 20);
+        if (length > 53) {
+            receiverData = readBytes(assetData, 52);
+        }
+        proxyId = uint8(assetData[length - 1]);
+
+        return (
+            proxyId,
+            token,
+            tokenId,
+            receiverData
+        );
+    }
 }
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol
index 5fa33cbef..9032658e7 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol
+++ b/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol
@@ -28,12 +28,12 @@ contract MixinAssetProxy is
 {
 
     /// @dev Transfers assets. Either succeeds or throws.
-    /// @param assetMetadata Encoded byte array.
+    /// @param assetData Encoded byte array.
     /// @param from Address to transfer asset from.
     /// @param to Address to transfer asset to.
     /// @param amount Amount of asset to transfer.
     function transferFrom(
-        bytes assetMetadata,
+        bytes assetData,
         address from,
         address to,
         uint256 amount
@@ -42,7 +42,7 @@ contract MixinAssetProxy is
         onlyAuthorized
     {
         transferFromInternal(
-            assetMetadata,
+            assetData,
             from,
             to,
             amount
@@ -50,12 +50,12 @@ contract MixinAssetProxy is
     }
 
     /// @dev Makes multiple transfers of assets. Either succeeds or throws.
-    /// @param assetMetadata Array of byte arrays encoded for the respective asset proxy.
+    /// @param assetData Array of byte arrays encoded for the respective asset proxy.
     /// @param from Array of addresses to transfer assets from.
     /// @param to Array of addresses to transfer assets to.
     /// @param amounts Array of amounts of assets to transfer.
     function batchTransferFrom(
-        bytes[] memory assetMetadata,
+        bytes[] memory assetData,
         address[] memory from,
         address[] memory to,
         uint256[] memory amounts
@@ -63,9 +63,9 @@ contract MixinAssetProxy is
         public
         onlyAuthorized
     {
-        for (uint256 i = 0; i < assetMetadata.length; i++) {
+        for (uint256 i = 0; i < assetData.length; i++) {
             transferFromInternal(
-                assetMetadata[i],
+                assetData[i],
                 from[i],
                 to[i],
                 amounts[i]
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetProxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetProxy.sol
index 7e1848889..22f43b12f 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetProxy.sol
+++ b/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetProxy.sol
@@ -26,12 +26,12 @@ contract IAssetProxy is
 {
 
     /// @dev Transfers assets. Either succeeds or throws.
-    /// @param assetMetadata Byte array encoded for the respective asset proxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
     /// @param from Address to transfer asset from.
     /// @param to Address to transfer asset to.
     /// @param amount Amount of asset to transfer.
     function transferFrom(
-        bytes assetMetadata,
+        bytes assetData,
         address from,
         address to,
         uint256 amount
@@ -39,12 +39,12 @@ contract IAssetProxy is
         external;
     
     /// @dev Makes multiple transfers of assets. Either succeeds or throws.
-    /// @param assetMetadata Array of byte arrays encoded for the respective asset proxy.
+    /// @param assetData Array of byte arrays encoded for the respective asset proxy.
     /// @param from Array of addresses to transfer assets from.
     /// @param to Array of addresses to transfer assets to.
     /// @param amounts Array of amounts of assets to transfer.
     function batchTransferFrom(
-        bytes[] memory assetMetadata,
+        bytes[] memory assetData,
         address[] memory from,
         address[] memory to,
         uint256[] memory amounts
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibAssetProxyErrors.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
index e0c7fc796..80180a0d9 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
+++ b/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
@@ -29,9 +29,9 @@ contract LibAssetProxyErrors {
     /// AssetProxy errors ///
     string constant ASSET_PROXY_ID_MISMATCH = "ASSET_PROXY_ID_MISMATCH";          // Proxy id in metadata does not match this proxy id.
     string constant INVALID_AMOUNT = "INVALID_AMOUNT";                            // Transfer amount must equal 1.
-    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                          // Transfer failed. 
+    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                          // Transfer failed.
 
     /// Length validation errors ///
     string constant LENGTH_21_REQUIRED = "LENGTH_21_REQUIRED";                    // Byte array must have a length of 21.
-    string constant LENGTH_53_REQUIRED = "LENGTH_53_REQUIRED";                    // Byte array must have a length of 53.
+    string constant LENGTH_AT_LEAST_53_REQUIRED = "LENGTH_AT_LEAST_53_REQUIRED";  // Byte array must have a length of at least 53.
 }
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol
index de9d65a53..a52cb56f9 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol
+++ b/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol
@@ -26,12 +26,12 @@ contract MAssetProxy is
 {
 
     /// @dev Internal version of `transferFrom`.
-    /// @param assetMetadata Encoded byte array.
+    /// @param assetData Encoded byte array.
     /// @param from Address to transfer asset from.
     /// @param to Address to transfer asset to.
     /// @param amount Amount of asset to transfer.
     function transferFromInternal(
-        bytes memory assetMetadata,
+        bytes memory assetData,
         address from,
         address to,
         uint256 amount
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol b/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
index b7b308069..51f99bafa 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
@@ -40,11 +40,11 @@ contract Exchange is
     string constant public VERSION = "2.0.1-alpha";
 
     // Mixins are instantiated in the order they are inherited
-    constructor (bytes memory _zrxProxyData)
+    constructor (bytes memory _zrxAssetData)
         public
         MixinExchangeCore()
         MixinMatchOrders()
-        MixinSettlement(_zrxProxyData)
+        MixinSettlement(_zrxAssetData)
         MixinSignatureValidator()
         MixinTransactions()
         MixinAssetProxyDispatcher()
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
index 8f9342739..e77d81c06 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -80,12 +80,12 @@ contract MixinAssetProxyDispatcher is
     }
 
     /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
-    /// @param assetMetadata Byte array encoded for the respective asset proxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
     /// @param from Address to transfer token from.
     /// @param to Address to transfer token to.
     /// @param amount Amount of token to transfer.
     function dispatchTransferFrom(
-        bytes memory assetMetadata,
+        bytes memory assetData,
         address from,
         address to,
         uint256 amount
@@ -96,16 +96,16 @@ contract MixinAssetProxyDispatcher is
         if (amount > 0) {
 
             // Lookup asset proxy
-            uint256 length = assetMetadata.length;
+            uint256 length = assetData.length;
             require(
                 length > 0,
                 LENGTH_GREATER_THAN_0_REQUIRED
             );
-            uint8 assetProxyId = uint8(assetMetadata[length - 1]);
+            uint8 assetProxyId = uint8(assetData[length - 1]);
             IAssetProxy assetProxy = assetProxies[assetProxyId];
 
             // transferFrom will either succeed or throw.
-            assetProxy.transferFrom(assetMetadata, from, to, amount);
+            assetProxy.transferFrom(assetData, from, to, amount);
         }
     }
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol
index 646d3ed58..83e9dfdf4 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol
@@ -40,7 +40,7 @@ contract MixinSettlement is
     bytes internal ZRX_PROXY_DATA;
 
     /// @dev Gets the ZRX metadata used for fee transfers.
-    function zrxProxyData()
+    function zrxAssetData()
         external
         view
         returns (bytes memory)
@@ -48,13 +48,13 @@ contract MixinSettlement is
         return ZRX_PROXY_DATA;
     }
 
-    /// TODO: _zrxProxyData should be a constant in production.
+    /// TODO: _zrxAssetData should be a constant in production.
     /// @dev Constructor sets the metadata that will be used for paying ZRX fees.
-    /// @param _zrxProxyData Byte array containing ERC20 proxy id concatenated with address of ZRX.
-    constructor (bytes memory _zrxProxyData)
+    /// @param _zrxAssetData Byte array containing ERC20 proxy id concatenated with address of ZRX.
+    constructor (bytes memory _zrxAssetData)
         public
     {
-        ZRX_PROXY_DATA = _zrxProxyData;
+        ZRX_PROXY_DATA = _zrxAssetData;
     }
 
     /// @dev Settles an order by transferring assets between counterparties.
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
index 0ad0710ce..e09f80bcc 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
@@ -40,7 +40,8 @@ contract MixinWrapperFunctions is
     function fillOrKillOrder(
         LibOrder.Order memory order,
         uint256 takerAssetFillAmount,
-        bytes memory signature)
+        bytes memory signature
+    )
         public
         returns (FillResults memory fillResults)
     {
@@ -65,7 +66,8 @@ contract MixinWrapperFunctions is
     function fillOrderNoThrow(
         LibOrder.Order memory order,
         uint256 takerAssetFillAmount,
-        bytes memory signature)
+        bytes memory signature
+    )
         public
         returns (FillResults memory fillResults)
     {
@@ -91,12 +93,12 @@ contract MixinWrapperFunctions is
         // |          | 0x0E0  |         |   8.  takerFeeAmount                        |
         // |          | 0x100  |         |   9.  expirationTimeSeconds                 |
         // |          | 0x120  |         |   10. salt                                  |
-        // |          | 0x140  |         |   11. Offset to makerAssetProxyMetadata (*) |
-        // |          | 0x160  |         |   12. Offset to takerAssetProxyMetadata (*) |
-        // |          | 0x180  | 32      | makerAssetProxyMetadata Length              |
-        // |          | 0x1A0  | **      | makerAssetProxyMetadata Contents            |
-        // |          | 0x1C0  | 32      | takerAssetProxyMetadata Length              |
-        // |          | 0x1E0  | **      | takerAssetProxyMetadata Contents            |
+        // |          | 0x140  |         |   11. Offset to makerAssetData (*)          |
+        // |          | 0x160  |         |   12. Offset to takerAssetData (*)          |
+        // |          | 0x180  | 32      | makerAssetData Length                       |
+        // |          | 0x1A0  | **      | makerAssetData Contents                     |
+        // |          | 0x1C0  | 32      | takerAssetData Length                       |
+        // |          | 0x1E0  | **      | takerAssetData Contents                     |
         // |          | 0x200  | 32      | signature Length                            |
         // |          | 0x220  | **      | signature Contents                          |
 
@@ -163,43 +165,43 @@ contract MixinWrapperFunctions is
             mstore(add(dataAreaEnd, 0xE0), mload(add(sourceOffset, 0xE0)))      // takerFeeAmount
             mstore(add(dataAreaEnd, 0x100), mload(add(sourceOffset, 0x100)))    // expirationTimeSeconds
             mstore(add(dataAreaEnd, 0x120), mload(add(sourceOffset, 0x120)))    // salt
-            mstore(add(dataAreaEnd, 0x140), mload(add(sourceOffset, 0x140)))    // Offset to makerAssetProxyMetadata
-            mstore(add(dataAreaEnd, 0x160), mload(add(sourceOffset, 0x160)))    // Offset to takerAssetProxyMetadata
+            mstore(add(dataAreaEnd, 0x140), mload(add(sourceOffset, 0x140)))    // Offset to makerAssetData
+            mstore(add(dataAreaEnd, 0x160), mload(add(sourceOffset, 0x160)))    // Offset to takerAssetData
             dataAreaEnd := add(dataAreaEnd, 0x180)
             sourceOffset := add(sourceOffset, 0x180)
 
-            // Write offset to <order.makerAssetProxyMetadata>
+            // Write offset to <order.makerAssetData>
             mstore(add(dataAreaStart, mul(10, 0x20)), sub(dataAreaEnd, dataAreaStart))
 
-            // Calculate length of <order.makerAssetProxyMetadata>
+            // Calculate length of <order.makerAssetData>
             arrayLenBytes := mload(sourceOffset)
             sourceOffset := add(sourceOffset, 0x20)
             arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)
 
-            // Write length of <order.makerAssetProxyMetadata>
+            // Write length of <order.makerAssetData>
             mstore(dataAreaEnd, arrayLenBytes)
             dataAreaEnd := add(dataAreaEnd, 0x20)
 
-            // Write contents of <order.makerAssetProxyMetadata>
+            // Write contents of <order.makerAssetData>
             for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
                 mstore(dataAreaEnd, mload(sourceOffset))
                 dataAreaEnd := add(dataAreaEnd, 0x20)
                 sourceOffset := add(sourceOffset, 0x20)
             }
 
-            // Write offset to <order.takerAssetProxyMetadata>
+            // Write offset to <order.takerAssetData>
             mstore(add(dataAreaStart, mul(11, 0x20)), sub(dataAreaEnd, dataAreaStart))
 
-            // Calculate length of <order.takerAssetProxyMetadata>
+            // Calculate length of <order.takerAssetData>
             arrayLenBytes := mload(sourceOffset)
             sourceOffset := add(sourceOffset, 0x20)
             arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)
 
-            // Write length of <order.takerAssetProxyMetadata>
+            // Write length of <order.takerAssetData>
             mstore(dataAreaEnd, arrayLenBytes)
             dataAreaEnd := add(dataAreaEnd, 0x20)
 
-            // Write contents of  <order.takerAssetProxyMetadata>
+            // Write contents of  <order.takerAssetData>
             for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
                 mstore(dataAreaEnd, mload(sourceOffset))
                 dataAreaEnd := add(dataAreaEnd, 0x20)
@@ -264,7 +266,8 @@ contract MixinWrapperFunctions is
     function batchFillOrders(
         LibOrder.Order[] memory orders,
         uint256[] memory takerAssetFillAmounts,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
     {
         for (uint256 i = 0; i < orders.length; i++) {
@@ -283,7 +286,8 @@ contract MixinWrapperFunctions is
     function batchFillOrKillOrders(
         LibOrder.Order[] memory orders,
         uint256[] memory takerAssetFillAmounts,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
     {
         for (uint256 i = 0; i < orders.length; i++) {
@@ -303,7 +307,8 @@ contract MixinWrapperFunctions is
     function batchFillOrdersNoThrow(
         LibOrder.Order[] memory orders,
         uint256[] memory takerAssetFillAmounts,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
     {
         for (uint256 i = 0; i < orders.length; i++) {
@@ -323,7 +328,8 @@ contract MixinWrapperFunctions is
     function marketSellOrders(
         LibOrder.Order[] memory orders,
         uint256 takerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (FillResults memory totalFillResults)
     {
@@ -366,7 +372,8 @@ contract MixinWrapperFunctions is
     function marketSellOrdersNoThrow(
         LibOrder.Order[] memory orders,
         uint256 takerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (FillResults memory totalFillResults)
     {
@@ -408,7 +415,8 @@ contract MixinWrapperFunctions is
     function marketBuyOrders(
         LibOrder.Order[] memory orders,
         uint256 makerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (FillResults memory totalFillResults)
     {
@@ -459,7 +467,8 @@ contract MixinWrapperFunctions is
     function marketBuyOrdersNoThrow(
         LibOrder.Order[] memory orders,
         uint256 makerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (FillResults memory totalFillResults)
     {
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
index 3ce5ef157..2c331dc34 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
@@ -28,7 +28,8 @@ contract IAssetProxyDispatcher {
     function registerAssetProxy(
         uint8 assetProxyId,
         address newAssetProxy,
-        address oldAssetProxy)
+        address oldAssetProxy
+    )
         external;
 
     /// @dev Gets an asset proxy.
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
index d973bf001..2f9a5bc7c 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
@@ -28,6 +28,7 @@ contract ITransactions {
         uint256 salt,
         address signer,
         bytes data,
-        bytes signature)
+        bytes signature
+    )
         external;
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
index 8682b394a..acd4f359c 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
@@ -33,7 +33,8 @@ contract IWrapperFunctions is
     function fillOrKillOrder(
         LibOrder.Order memory order,
         uint256 takerAssetFillAmount,
-        bytes memory signature)
+        bytes memory signature
+    )
         public
         returns (LibFillResults.FillResults memory fillResults);
 
@@ -46,7 +47,8 @@ contract IWrapperFunctions is
     function fillOrderNoThrow(
         LibOrder.Order memory order,
         uint256 takerAssetFillAmount,
-        bytes memory signature)
+        bytes memory signature
+    )
         public
         returns (LibFillResults.FillResults memory fillResults);
 
@@ -57,7 +59,8 @@ contract IWrapperFunctions is
     function batchFillOrders(
         LibOrder.Order[] memory orders,
         uint256[] memory takerAssetFillAmounts,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public;
 
     /// @dev Synchronously executes multiple calls of fillOrKill.
@@ -67,7 +70,8 @@ contract IWrapperFunctions is
     function batchFillOrKillOrders(
         LibOrder.Order[] memory orders,
         uint256[] memory takerAssetFillAmounts,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public;
 
     /// @dev Fills an order with specified parameters and ECDSA signature.
@@ -78,7 +82,8 @@ contract IWrapperFunctions is
     function batchFillOrdersNoThrow(
         LibOrder.Order[] memory orders,
         uint256[] memory takerAssetFillAmounts,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public;
 
     /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
@@ -89,7 +94,8 @@ contract IWrapperFunctions is
     function marketSellOrders(
         LibOrder.Order[] memory orders,
         uint256 takerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (LibFillResults.FillResults memory totalFillResults);
 
@@ -102,7 +108,8 @@ contract IWrapperFunctions is
     function marketSellOrdersNoThrow(
         LibOrder.Order[] memory orders,
         uint256 takerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (LibFillResults.FillResults memory totalFillResults);
 
@@ -114,7 +121,8 @@ contract IWrapperFunctions is
     function marketBuyOrders(
         LibOrder.Order[] memory orders,
         uint256 makerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (LibFillResults.FillResults memory totalFillResults);
 
@@ -127,7 +135,8 @@ contract IWrapperFunctions is
     function marketBuyOrdersNoThrow(
         LibOrder.Order[] memory orders,
         uint256 makerAssetFillAmount,
-        bytes[] memory signatures)
+        bytes[] memory signatures
+    )
         public
         returns (LibFillResults.FillResults memory totalFillResults);
 
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
index 87c5f6361..82eafb529 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
@@ -33,12 +33,12 @@ contract MAssetProxyDispatcher is
     );
 
     /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
-    /// @param assetMetadata Byte array encoded for the respective asset proxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
     /// @param from Address to transfer token from.
     /// @param to Address to transfer token to.
     /// @param amount Amount of token to transfer.
     function dispatchTransferFrom(
-        bytes memory assetMetadata,
+        bytes memory assetData,
         address from,
         address to,
         uint256 amount
diff --git a/packages/contracts/src/contracts/current/test/DummyERC20Token/DummyERC20Token.sol b/packages/contracts/src/contracts/current/test/DummyERC20Token/DummyERC20Token.sol
index 0c7b18c0c..b2fe2df06 100644
--- a/packages/contracts/src/contracts/current/test/DummyERC20Token/DummyERC20Token.sol
+++ b/packages/contracts/src/contracts/current/test/DummyERC20Token/DummyERC20Token.sol
@@ -31,7 +31,8 @@ contract DummyERC20Token is Mintable, Ownable {
         string _name,
         string _symbol,
         uint256 _decimals,
-        uint256 _totalSupply)
+        uint256 _totalSupply
+    )
         public
     {
         name = _name;
diff --git a/packages/contracts/src/contracts/current/test/DummyERC721Receiver/DummyERC721Receiver.sol b/packages/contracts/src/contracts/current/test/DummyERC721Receiver/DummyERC721Receiver.sol
new file mode 100644
index 000000000..c584d0b54
--- /dev/null
+++ b/packages/contracts/src/contracts/current/test/DummyERC721Receiver/DummyERC721Receiver.sol
@@ -0,0 +1,63 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 Smart Contract Solutions, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../tokens/ERC721Token/IERC721Receiver.sol";
+
+contract DummyERC721Receiver is
+    IERC721Receiver
+{
+
+    event TokenReceived(
+        address from,
+        uint256 tokenId,
+        bytes data
+    );
+
+    /**
+    * @notice Handle the receipt of an NFT
+    * @dev The ERC721 smart contract calls this function on the recipient
+    *  after a `safetransfer`. This function MAY throw to revert and reject the
+    *  transfer. This function MUST use 50,000 gas or less. Return of other
+    *  than the magic value MUST result in the transaction being reverted.
+    *  Note: the contract address is always the message sender.
+    * @param _from The sending address
+    * @param _tokenId The NFT identifier which is being transfered
+    * @param _data Additional data with no specified format
+    * @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
+    */
+    function onERC721Received(
+        address _from,
+        uint256 _tokenId,
+        bytes _data
+    )
+        public
+        returns (bytes4)
+    {
+        emit TokenReceived(_from, _tokenId, _data);
+        return ERC721_RECEIVED;
+    }
+}
diff --git a/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol b/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol
index 369a2950d..5503eb2f2 100644
--- a/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol
+++ b/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol
@@ -34,7 +34,8 @@ contract DummyERC721Token is
     */
     constructor (
         string name,
-        string symbol)
+        string symbol
+    )
         public
         ERC721Token(name, symbol)
     {}
diff --git a/packages/contracts/src/contracts/current/test/TestAssetDataDecoders/TestAssetDataDecoders.sol b/packages/contracts/src/contracts/current/test/TestAssetDataDecoders/TestAssetDataDecoders.sol
new file mode 100644
index 000000000..2c6a8fdb0
--- /dev/null
+++ b/packages/contracts/src/contracts/current/test/TestAssetDataDecoders/TestAssetDataDecoders.sol
@@ -0,0 +1,77 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/AssetProxy/ERC20Proxy.sol";
+import "../../protocol/AssetProxy/ERC721Proxy.sol";
+
+contract TestAssetDataDecoders is
+    ERC20Proxy,
+    ERC721Proxy
+{
+
+    /// @dev Decodes ERC20 Asset data.
+    /// @param assetData Encoded byte array.
+    /// @return proxyId Intended ERC20 proxy id.
+    /// @return token ERC20 token address.
+    function publicDecodeERC20Data(bytes memory assetData)
+        public
+        pure
+        returns (
+            uint8 proxyId,
+            address token
+        )
+    {
+        (proxyId, token) = decodeERC20AssetData(assetData);
+        return (proxyId, token);
+    }
+
+    /// @dev Decodes ERC721 Asset data.
+    /// @param assetData Encoded byte array.
+    /// @return proxyId Intended ERC721 proxy id.
+    /// @return token ERC721 token address.
+    /// @return tokenId ERC721 token id.
+    /// @return receiverData Additional data with no specific format, which
+    ///                      is passed to the receiving contract's onERC721Received.
+    function publicDecodeERC721Data(bytes memory assetData)
+        public
+        pure
+        returns (
+            uint8 proxyId,
+            address token,
+            uint256 tokenId,
+            bytes memory receiverData
+        )
+    {
+        (
+            proxyId,
+            token,
+            tokenId,
+            receiverData
+        ) = decodeERC721AssetData(assetData);
+
+        return (
+            proxyId,
+            token,
+            tokenId,
+            receiverData
+        );
+    }
+}
diff --git a/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
index 11ca0617d..2ae69e0ef 100644
--- a/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
+++ b/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
@@ -23,12 +23,12 @@ import "../../protocol/Exchange/MixinAssetProxyDispatcher.sol";
 
 contract TestAssetProxyDispatcher is MixinAssetProxyDispatcher {
     function publicDispatchTransferFrom(
-        bytes memory assetMetadata,
+        bytes memory assetData,
         address from,
         address to,
         uint256 amount)
         public
     {
-        dispatchTransferFrom(assetMetadata, from, to, amount);
+        dispatchTransferFrom(assetData, from, to, amount);
     }
 }
diff --git a/packages/contracts/src/contracts/current/test/TestLibBytes/TestLibBytes.sol b/packages/contracts/src/contracts/current/test/TestLibBytes/TestLibBytes.sol
index 69554605d..22c84504c 100644
--- a/packages/contracts/src/contracts/current/test/TestLibBytes/TestLibBytes.sol
+++ b/packages/contracts/src/contracts/current/test/TestLibBytes/TestLibBytes.sol
@@ -68,7 +68,8 @@ contract TestLibBytes is
     /// @return address from byte array.
     function publicReadAddress(
         bytes memory b,
-        uint256 index)
+        uint256 index
+    )
         public
         pure
         returns (address result)
@@ -84,7 +85,8 @@ contract TestLibBytes is
     function publicWriteAddress(
         bytes memory b,
         uint256 index,
-        address input)
+        address input
+    )
         public
         pure
         returns (bytes memory)
@@ -99,7 +101,8 @@ contract TestLibBytes is
     /// @return bytes32 value from byte array.
     function publicReadBytes32(
         bytes memory b,
-        uint256 index)
+        uint256 index
+    )
         public
         pure
         returns (bytes32 result)
@@ -115,7 +118,8 @@ contract TestLibBytes is
     function publicWriteBytes32(
         bytes memory b,
         uint256 index,
-        bytes32 input)
+        bytes32 input
+    )
         public
         pure
         returns (bytes memory)
@@ -130,7 +134,8 @@ contract TestLibBytes is
     /// @return uint256 value from byte array.
     function publicReadUint256(
         bytes memory b,
-        uint256 index)
+        uint256 index
+    )
         public
         pure
         returns (uint256 result)
@@ -146,7 +151,8 @@ contract TestLibBytes is
     function publicWriteUint256(
         bytes memory b,
         uint256 index,
-        uint256 input)
+        uint256 input
+    )
         public
         pure
         returns (bytes memory)
@@ -166,4 +172,38 @@ contract TestLibBytes is
         result = readFirst4(b);
         return result;
     }
+
+    /// @dev Reads nested bytes from a specific position.
+    /// @param b Byte array containing nested bytes.
+    /// @param index Index of nested bytes.
+    /// @return result Nested bytes.
+    function publicReadBytes(
+        bytes memory b,
+        uint256 index
+    )
+        public
+        pure
+        returns (bytes memory result)
+    {
+        result = readBytes(b, index);
+        return result;
+    }
+
+    /// @dev Inserts bytes at a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input bytes to insert.
+    /// @return b Updated input byte array
+    function publicWriteBytes(
+        bytes memory b,
+        uint256 index,
+        bytes memory input
+    )
+        public
+        pure
+        returns (bytes memory)
+    {
+        writeBytes(b, index, input);
+        return b;
+    }
 }
diff --git a/packages/contracts/src/contracts/current/test/TestLibMem/TestLibMem.sol b/packages/contracts/src/contracts/current/test/TestLibMem/TestLibMem.sol
new file mode 100644
index 000000000..b7e2e06b8
--- /dev/null
+++ b/packages/contracts/src/contracts/current/test/TestLibMem/TestLibMem.sol
@@ -0,0 +1,56 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../utils/LibMem/LibMem.sol";
+
+contract TestLibMem is
+    LibMem
+{
+
+    /// @dev Copies a block of memory from one location to another.
+    /// @param mem Memory contents we want to apply memCopy to
+    /// @param dest Destination offset into <mem>.
+    /// @param source Source offset into <mem>.
+    /// @param length Length of bytes to copy from <source> to <dest>
+    /// @return mem Memory contents after calling memCopy.
+    function testMemcpy(
+        bytes mem,
+        uint256 dest,
+        uint256 source,
+        uint256 length
+    )
+        public // not external, we need input in memory
+        pure
+        returns (bytes)
+    {
+        // Sanity check. Overflows are not checked.
+        require(source + length <= mem.length);
+        require(dest + length <= mem.length);
+
+        // Get pointer to memory contents
+        uint256 offset = getMemAddress(mem) + 32;
+
+        // Execute memCopy adjusted for memory array location
+        memCopy(offset + dest, offset + source, length);
+
+        // Return modified memory contents
+        return mem;
+    }
+}
diff --git a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol b/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
index df2221c93..d1d10476f 100644
--- a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
+++ b/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
@@ -18,14 +18,18 @@
 
 pragma solidity ^0.4.24;
 
-contract LibBytes {
+import "../LibMem/LibMem.sol";
+
+contract LibBytes is
+    LibMem
+{
 
     // Revert reasons
-    string constant GT_ZERO_LENGTH_REQUIRED = "Length must be greater than 0.";
-    string constant GTE_4_LENGTH_REQUIRED = "Length must be greater than or equal to 4.";
-    string constant GTE_20_LENGTH_REQUIRED = "Length must be greater than or equal to 20.";
-    string constant GTE_32_LENGTH_REQUIRED = "Length must be greater than or equal to 32.";
-    string constant INDEX_OUT_OF_BOUNDS = "Specified array index is out of bounds.";
+    string constant GREATER_THAN_ZERO_LENGTH_REQUIRED = "GREATER_THAN_ZERO_LENGTH_REQUIRED";
+    string constant GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED";
+    string constant GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED";
+    string constant GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED";
+    string constant GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED";
 
     /// @dev Pops the last byte off of a byte array by modifying its length.
     /// @param b Byte array that will be modified.
@@ -37,12 +41,12 @@ contract LibBytes {
     {
         require(
             b.length > 0,
-            GT_ZERO_LENGTH_REQUIRED
+            GREATER_THAN_ZERO_LENGTH_REQUIRED
         );
 
         // Store last byte.
         result = b[b.length - 1];
-        
+
         assembly {
             // Decrement length of byte array.
             let newLen := sub(mload(b), 1)
@@ -61,7 +65,7 @@ contract LibBytes {
     {
         require(
             b.length >= 20,
-            GTE_20_LENGTH_REQUIRED
+            GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED
         );
 
         // Store last 20 bytes.
@@ -124,8 +128,8 @@ contract LibBytes {
     {
         require(
             b.length >= index + 20,  // 20 is length of address
-            GTE_20_LENGTH_REQUIRED
-        ); 
+            GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED
+        );
 
         // Add offset to index:
         // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
@@ -156,8 +160,8 @@ contract LibBytes {
     {
         require(
             b.length >= index + 20,  // 20 is length of address
-            GTE_20_LENGTH_REQUIRED
-        ); 
+            GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED
+        );
 
         // Add offset to index:
         // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
@@ -195,7 +199,7 @@ contract LibBytes {
     {
         require(
             b.length >= index + 32,
-            GTE_32_LENGTH_REQUIRED
+            GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED
         );
 
         // Arrays are prefixed by a 256 bit length parameter
@@ -222,7 +226,7 @@ contract LibBytes {
     {
         require(
             b.length >= index + 32,
-            GTE_32_LENGTH_REQUIRED
+            GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED
         );
 
         // Arrays are prefixed by a 256 bit length parameter
@@ -274,11 +278,72 @@ contract LibBytes {
     {
         require(
             b.length >= 4,
-            GTE_4_LENGTH_REQUIRED
+            GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED
         );
         assembly {
             result := mload(add(b, 32))
         }
         return result;
     }
+
+    /// @dev Reads nested bytes from a specific position.
+    /// @param b Byte array containing nested bytes.
+    /// @param index Index of nested bytes.
+    /// @return result Nested bytes.
+    function readBytes(
+        bytes memory b,
+        uint256 index
+    )
+        internal
+        pure
+        returns (bytes memory result)
+    {
+        // Read length of nested bytes
+        uint256 nestedBytesLength = readUint256(b, index);
+        index += 32;
+
+        // Assert length of <b> is valid, given
+        // length of nested bytes
+        require(
+            b.length >= index + nestedBytesLength,
+            GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED
+        );
+
+        // Allocate memory and copy value to result
+        result = new bytes(nestedBytesLength);
+        memCopy(
+            getMemAddress(result) + 32, // +32 skips array length
+            getMemAddress(b) + index + 32,
+            nestedBytesLength
+        );
+
+        return result;
+    }
+
+    /// @dev Inserts bytes at a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input bytes to insert.
+    function writeBytes(
+        bytes memory b,
+        uint256 index,
+        bytes memory input
+    )
+        internal
+        pure
+    {
+        // Assert length of <b> is valid, given
+        // length of input
+        require(
+            b.length >= index + 32 /* 32 bytes to store length */ + input.length,
+            GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED
+        );
+
+        // Copy <input> into <b>
+        memCopy(
+            getMemAddress(b) + 32 + index,  // +32 to skip length of <b>
+            getMemAddress(input),           // includes length of <input>
+            input.length + 32               // +32 bytes to store <input> length
+        );
+    }
 }
diff --git a/packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol b/packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol
new file mode 100644
index 000000000..6afb9973a
--- /dev/null
+++ b/packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol
@@ -0,0 +1,140 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+contract LibMem
+{
+
+    /// @dev Gets the memory address for a byte array.
+    /// @param input Byte array to lookup.
+    /// @return memoryAddress Memory address of byte array.
+    function getMemAddress(bytes memory input)
+        internal
+        pure
+        returns (uint256 memoryAddress)
+    {
+        assembly {
+            memoryAddress := input
+        }
+        return memoryAddress;
+    }
+
+    /// @dev Copies `length` bytes from memory location `source` to `dest`.
+    /// @param dest memory address to copy bytes to.
+    /// @param source memory address to copy bytes from.
+    /// @param length number of bytes to copy.
+    function memCopy(
+        uint256 dest,
+        uint256 source,
+        uint256 length
+    )
+        internal
+        pure
+    {
+        if (length < 32) {
+            // Handle a partial word by reading destination and masking
+            // off the bits we are interested in.
+            // This correctly handles overlap, zero lengths and source == dest
+            assembly {
+                let mask := sub(exp(256, sub(32, length)), 1)
+                let s := and(mload(source), not(mask))
+                let d := and(mload(dest), mask)
+                mstore(dest, or(s, d))
+            }
+        } else {
+            // Skip the O(length) loop when source == dest.
+            if (source == dest) {
+                return;
+            }
+
+            // For large copies we copy whole words at a time. The final
+            // word is aligned to the end of the range (instead of after the
+            // previous) to handle partial words. So a copy will look like this:
+            //
+            //  ####
+            //      ####
+            //          ####
+            //            ####
+            //
+            // We handle overlap in the source and destination range by
+            // changing the copying direction. This prevents us from
+            // overwriting parts of source that we still need to copy.
+            //
+            // This correctly handles source == dest
+            //
+            if (source > dest) {
+                assembly {
+                    // Record the total number of full words to copy
+                    let nWords := div(length, 32)
+
+                    // We subtract 32 from `sEnd` and `dEnd` because it
+                    // is easier to compare with in the loop, and these
+                    // are also the addresses we need for copying the
+                    // last bytes.
+                    length := sub(length, 32)
+                    let sEnd := add(source, length)
+                    let dEnd := add(dest, length)
+
+                    // Remember the last 32 bytes of source
+                    // This needs to be done here and not after the loop
+                    // because we may have overwritten the last bytes in
+                    // source already due to overlap.
+                    let last := mload(sEnd)
+
+                    // Copy whole words front to back
+                    for {let i := 0} lt(i, nWords) {i := add(i, 1)} {
+                        mstore(dest, mload(source))
+                        source := add(source, 32)
+                        dest := add(dest, 32)
+                    }
+
+                    // Write the last 32 bytes
+                    mstore(dEnd, last)
+                }
+            } else {
+                assembly {
+                    // Record the total number of full words to copy
+                    let nWords := div(length, 32)
+
+                    // We subtract 32 from `sEnd` and `dEnd` because those
+                    // are the starting points when copying a word at the end.
+                    length := sub(length, 32)
+                    let sEnd := add(source, length)
+                    let dEnd := add(dest, length)
+
+                    // Remember the first 32 bytes of source
+                    // This needs to be done here and not after the loop
+                    // because we may have overwritten the first bytes in
+                    // source already due to overlap.
+                    let first := mload(source)
+
+                    // Copy whole words back to front
+                    for {let i := 0} lt(i, nWords) {i := add(i, 1)} {
+                        mstore(dEnd, mload(sEnd))
+                        sEnd := sub(sEnd, 32)
+                        dEnd := sub(dEnd, 32)
+                    }
+
+                    // Write the first 32 bytes
+                    mstore(dest, first)
+                }
+            }
+        }
+    }
+}
diff --git a/packages/contracts/src/utils/artifacts.ts b/packages/contracts/src/utils/artifacts.ts
index 357c66a0a..bf7221d6d 100644
--- a/packages/contracts/src/utils/artifacts.ts
+++ b/packages/contracts/src/utils/artifacts.ts
@@ -2,6 +2,7 @@ import { ContractArtifact } from '@0xproject/sol-compiler';
 
 import * as AssetProxyOwner from '../artifacts/AssetProxyOwner.json';
 import * as DummyERC20Token from '../artifacts/DummyERC20Token.json';
+import * as DummyERC721Receiver from '../artifacts/DummyERC721Receiver.json';
 import * as DummyERC721Token from '../artifacts/DummyERC721Token.json';
 import * as ERC20Proxy from '../artifacts/ERC20Proxy.json';
 import * as ERC721Proxy from '../artifacts/ERC721Proxy.json';
@@ -9,8 +10,10 @@ import * as Exchange from '../artifacts/Exchange.json';
 import * as MixinAuthorizable from '../artifacts/MixinAuthorizable.json';
 import * as MultiSigWallet from '../artifacts/MultiSigWallet.json';
 import * as MultiSigWalletWithTimeLock from '../artifacts/MultiSigWalletWithTimeLock.json';
+import * as TestAssetDataDecoders from '../artifacts/TestAssetDataDecoders.json';
 import * as TestAssetProxyDispatcher from '../artifacts/TestAssetProxyDispatcher.json';
 import * as TestLibBytes from '../artifacts/TestLibBytes.json';
+import * as TestLibMem from '../artifacts/TestLibMem.json';
 import * as TestLibs from '../artifacts/TestLibs.json';
 import * as TestSignatureValidator from '../artifacts/TestSignatureValidator.json';
 import * as TokenRegistry from '../artifacts/TokenRegistry.json';
@@ -21,6 +24,7 @@ import * as ZRX from '../artifacts/ZRXToken.json';
 export const artifacts = {
     AssetProxyOwner: (AssetProxyOwner as any) as ContractArtifact,
     DummyERC20Token: (DummyERC20Token as any) as ContractArtifact,
+    DummyERC721Receiver: (DummyERC721Receiver as any) as ContractArtifact,
     DummyERC721Token: (DummyERC721Token as any) as ContractArtifact,
     ERC20Proxy: (ERC20Proxy as any) as ContractArtifact,
     ERC721Proxy: (ERC721Proxy as any) as ContractArtifact,
@@ -30,7 +34,9 @@ export const artifacts = {
     MultiSigWallet: (MultiSigWallet as any) as ContractArtifact,
     MultiSigWalletWithTimeLock: (MultiSigWalletWithTimeLock as any) as ContractArtifact,
     TestAssetProxyDispatcher: (TestAssetProxyDispatcher as any) as ContractArtifact,
+    TestAssetDataDecoders: (TestAssetDataDecoders as any) as ContractArtifact,
     TestLibBytes: (TestLibBytes as any) as ContractArtifact,
+    TestLibMem: (TestLibMem as any) as ContractArtifact,
     TestLibs: (TestLibs as any) as ContractArtifact,
     TestSignatureValidator: (TestSignatureValidator as any) as ContractArtifact,
     TokenRegistry: (TokenRegistry as any) as ContractArtifact,
diff --git a/packages/contracts/src/utils/constants.ts b/packages/contracts/src/utils/constants.ts
index fa2a4af3c..af3f26d82 100644
--- a/packages/contracts/src/utils/constants.ts
+++ b/packages/contracts/src/utils/constants.ts
@@ -19,11 +19,11 @@ const TESTRPC_PRIVATE_KEYS_STRINGS = [
 export const constants = {
     INVALID_OPCODE: 'invalid opcode',
     REVERT: 'revert',
-    LIB_BYTES_GT_ZERO_LENGTH_REQUIRED: 'Length must be greater than 0.',
-    LIB_BYTES_GTE_4_LENGTH_REQUIRED: 'Length must be greater than or equal to 4.',
-    LIB_BYTES_GTE_20_LENGTH_REQUIRED: 'Length must be greater than or equal to 20.',
-    LIB_BYTES_GTE_32_LENGTH_REQUIRED: 'Length must be greater than or equal to 32.',
-    LIB_BYTES_INDEX_OUT_OF_BOUNDS: 'Specified array index is out of bounds.',
+    LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED: 'GREATER_THAN_ZERO_LENGTH_REQUIRED',
+    LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED',
+    LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED',
+    LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED',
+    LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED',
     ERC20_INSUFFICIENT_BALANCE: 'Insufficient balance to complete transfer.',
     ERC20_INSUFFICIENT_ALLOWANCE: 'Insufficient allowance to complete transfer.',
     TESTRPC_NETWORK_ID: 50,
diff --git a/packages/contracts/src/utils/match_order_tester.ts b/packages/contracts/src/utils/match_order_tester.ts
index f4f7f965b..fbb1b99db 100644
--- a/packages/contracts/src/utils/match_order_tester.ts
+++ b/packages/contracts/src/utils/match_order_tester.ts
@@ -237,11 +237,11 @@ export class MatchOrderTester {
         const expectedNewERC20BalancesByOwner = _.cloneDeep(erc20BalancesByOwner);
         const expectedNewERC721TokenIdsByOwner = _.cloneDeep(erc721TokenIdsByOwner);
         // Left Maker Asset (Right Taker Asset)
-        const makerAssetProxyIdLeft = assetProxyUtils.decodeProxyDataId(signedOrderLeft.makerAssetData);
+        const makerAssetProxyIdLeft = assetProxyUtils.decodeAssetDataId(signedOrderLeft.makerAssetData);
         if (makerAssetProxyIdLeft === AssetProxyId.ERC20) {
             // Decode asset data
-            const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(signedOrderLeft.makerAssetData);
-            const makerAssetAddressLeft = erc20ProxyData.tokenAddress;
+            const erc20AssetData = assetProxyUtils.decodeERC20AssetData(signedOrderLeft.makerAssetData);
+            const makerAssetAddressLeft = erc20AssetData.tokenAddress;
             const takerAssetAddressRight = makerAssetAddressLeft;
             // Left Maker
             expectedNewERC20BalancesByOwner[makerAddressLeft][makerAssetAddressLeft] = expectedNewERC20BalancesByOwner[
@@ -259,9 +259,9 @@ export class MatchOrderTester {
             ][makerAssetAddressLeft].add(expectedTransferAmounts.amountReceivedByTaker);
         } else if (makerAssetProxyIdLeft === AssetProxyId.ERC721) {
             // Decode asset data
-            const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(signedOrderLeft.makerAssetData);
-            const makerAssetAddressLeft = erc721ProxyData.tokenAddress;
-            const makerAssetIdLeft = erc721ProxyData.tokenId;
+            const erc721AssetData = assetProxyUtils.decodeERC721AssetData(signedOrderLeft.makerAssetData);
+            const makerAssetAddressLeft = erc721AssetData.tokenAddress;
+            const makerAssetIdLeft = erc721AssetData.tokenId;
             const takerAssetAddressRight = makerAssetAddressLeft;
             const takerAssetIdRight = makerAssetIdLeft;
             // Left Maker
@@ -272,11 +272,11 @@ export class MatchOrderTester {
         }
         // Left Taker Asset (Right Maker Asset)
         // Note: This exchange is only between the order makers: the Taker does not receive any of the left taker asset.
-        const takerAssetProxyIdLeft = assetProxyUtils.decodeProxyDataId(signedOrderLeft.takerAssetData);
+        const takerAssetProxyIdLeft = assetProxyUtils.decodeAssetDataId(signedOrderLeft.takerAssetData);
         if (takerAssetProxyIdLeft === AssetProxyId.ERC20) {
             // Decode asset data
-            const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(signedOrderLeft.takerAssetData);
-            const takerAssetAddressLeft = erc20ProxyData.tokenAddress;
+            const erc20AssetData = assetProxyUtils.decodeERC20AssetData(signedOrderLeft.takerAssetData);
+            const takerAssetAddressLeft = erc20AssetData.tokenAddress;
             const makerAssetAddressRight = takerAssetAddressLeft;
             // Left Maker
             expectedNewERC20BalancesByOwner[makerAddressLeft][takerAssetAddressLeft] = expectedNewERC20BalancesByOwner[
@@ -290,9 +290,9 @@ export class MatchOrderTester {
             );
         } else if (takerAssetProxyIdLeft === AssetProxyId.ERC721) {
             // Decode asset data
-            const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(signedOrderRight.makerAssetData);
-            const makerAssetAddressRight = erc721ProxyData.tokenAddress;
-            const makerAssetIdRight = erc721ProxyData.tokenId;
+            const erc721AssetData = assetProxyUtils.decodeERC721AssetData(signedOrderRight.makerAssetData);
+            const makerAssetAddressRight = erc721AssetData.tokenAddress;
+            const makerAssetIdRight = erc721AssetData.tokenId;
             const takerAssetAddressLeft = makerAssetAddressRight;
             const takerAssetIdLeft = makerAssetIdRight;
             // Right Maker
diff --git a/packages/contracts/src/utils/types.ts b/packages/contracts/src/utils/types.ts
index 491890fa1..bb8c12088 100644
--- a/packages/contracts/src/utils/types.ts
+++ b/packages/contracts/src/utils/types.ts
@@ -90,11 +90,14 @@ export enum ContractName {
     AccountLevels = 'AccountLevels',
     EtherDelta = 'EtherDelta',
     Arbitrage = 'Arbitrage',
+    TestAssetDataDecoders = 'TestAssetDataDecoders',
     TestAssetProxyDispatcher = 'TestAssetProxyDispatcher',
+    TestLibMem = 'TestLibMem',
     TestLibs = 'TestLibs',
     TestSignatureValidator = 'TestSignatureValidator',
     ERC20Proxy = 'ERC20Proxy',
     ERC721Proxy = 'ERC721Proxy',
+    DummyERC721Receiver = 'DummyERC721Receiver',
     DummyERC721Token = 'DummyERC721Token',
     TestLibBytes = 'TestLibBytes',
     Authorizable = 'Authorizable',
diff --git a/packages/contracts/test/asset_proxy/decoder.ts b/packages/contracts/test/asset_proxy/decoder.ts
new file mode 100644
index 000000000..d4fae1601
--- /dev/null
+++ b/packages/contracts/test/asset_proxy/decoder.ts
@@ -0,0 +1,103 @@
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { BigNumber } from '@0xproject/utils';
+import * as chai from 'chai';
+import ethUtil = require('ethereumjs-util');
+
+import { TestAssetDataDecodersContract } from '../../src/generated_contract_wrappers/test_asset_data_decoders';
+import { artifacts } from '../../src/utils/artifacts';
+import { chaiSetup } from '../../src/utils/chai_setup';
+import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('TestAssetDataDecoders', () => {
+    let testAssetProxyDecoder: TestAssetDataDecodersContract;
+    let testAddress: string;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        // Setup accounts & addresses
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        testAddress = accounts[0];
+        // Deploy TestLibMem
+        testAssetProxyDecoder = await TestAssetDataDecodersContract.deployFrom0xArtifactAsync(
+            artifacts.TestAssetDataDecoders,
+            provider,
+            txDefaults,
+        );
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    describe('Asset Data Decoders', () => {
+        it('should correctly decode ERC20 asset data)', async () => {
+            const encodedAssetData = assetProxyUtils.encodeERC20AssetData(testAddress);
+            const expectedDecodedAssetData = assetProxyUtils.decodeERC20AssetData(encodedAssetData);
+            let decodedAssetProxyId: number;
+            let decodedTokenAddress: string;
+            [decodedAssetProxyId, decodedTokenAddress] = await testAssetProxyDecoder.publicDecodeERC20Data.callAsync(
+                encodedAssetData,
+            );
+            expect(decodedAssetProxyId).to.be.equal(expectedDecodedAssetData.assetProxyId);
+            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
+        });
+
+        it('should correctly decode ERC721 asset data', async () => {
+            const tokenId = generatePseudoRandomSalt();
+            const encodedAssetData = assetProxyUtils.encodeERC721AssetData(testAddress, tokenId);
+            const expectedDecodedAssetData = assetProxyUtils.decodeERC721AssetData(encodedAssetData);
+            let decodedAssetProxyId: number;
+            let decodedTokenAddress: string;
+            let decodedTokenId: BigNumber;
+            let decodedData: string;
+            [
+                decodedAssetProxyId,
+                decodedTokenAddress,
+                decodedTokenId,
+                decodedData,
+            ] = await testAssetProxyDecoder.publicDecodeERC721Data.callAsync(encodedAssetData);
+            expect(decodedAssetProxyId).to.be.equal(expectedDecodedAssetData.assetProxyId);
+            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
+            expect(decodedTokenId).to.be.bignumber.equal(expectedDecodedAssetData.tokenId);
+            expect(decodedData).to.be.equal(expectedDecodedAssetData.receiverData);
+        });
+
+        it('should correctly decode ERC721 asset data with receiver data', async () => {
+            const tokenId = generatePseudoRandomSalt();
+            const receiverDataFirst32Bytes = ethUtil.bufferToHex(
+                assetProxyUtils.encodeUint256(generatePseudoRandomSalt()),
+            );
+            const receiverDataExtraBytes = 'FFFF';
+            // We add extra bytes to generate a value that doesn't fit perfectly into one word
+            const receiverData = receiverDataFirst32Bytes + receiverDataExtraBytes;
+            const encodedAssetData = assetProxyUtils.encodeERC721AssetData(testAddress, tokenId, receiverData);
+            const expectedDecodedAssetData = assetProxyUtils.decodeERC721AssetData(encodedAssetData);
+            let decodedAssetProxyId: number;
+            let decodedTokenAddress: string;
+            let decodedTokenId: BigNumber;
+            let decodedReceiverData: string;
+            [
+                decodedAssetProxyId,
+                decodedTokenAddress,
+                decodedTokenId,
+                decodedReceiverData,
+            ] = await testAssetProxyDecoder.publicDecodeERC721Data.callAsync(encodedAssetData);
+            expect(decodedAssetProxyId).to.be.equal(expectedDecodedAssetData.assetProxyId);
+            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
+            expect(decodedTokenId).to.be.bignumber.equal(expectedDecodedAssetData.tokenId);
+            expect(decodedReceiverData).to.be.equal(expectedDecodedAssetData.receiverData);
+        });
+    });
+});
diff --git a/packages/contracts/test/asset_proxy/proxies.ts b/packages/contracts/test/asset_proxy/proxies.ts
index d14280c5f..08376ccfb 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.ts
@@ -1,24 +1,33 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
-import { assetProxyUtils } from '@0xproject/order-utils';
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
+import { LogWithDecodedArgs } from 'ethereum-types';
+import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 
 import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import {
+    DummyERC721ReceiverContract,
+    TokenReceivedContractEventArgs,
+} from '../../src/generated_contract_wrappers/dummy_e_r_c721_receiver';
 import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
 import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
 import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
+import { artifacts } from '../../src/utils/artifacts';
 import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
 import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { provider, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { LogDecoder } from '../../src/utils/log_decoder';
+import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 
+// tslint:disable:no-unnecessary-type-assertion
 describe('Asset Transfer Proxies', () => {
     let owner: string;
     let notAuthorized: string;
@@ -28,6 +37,7 @@ describe('Asset Transfer Proxies', () => {
 
     let zrxToken: DummyERC20TokenContract;
     let erc721Token: DummyERC721TokenContract;
+    let erc721Receiver: DummyERC721ReceiverContract;
     let erc20Proxy: ERC20ProxyContract;
     let erc721Proxy: ERC721ProxyContract;
 
@@ -69,6 +79,11 @@ describe('Asset Transfer Proxies', () => {
             }),
             constants.AWAIT_TRANSACTION_MINED_MS,
         );
+        erc721Receiver = await DummyERC721ReceiverContract.deployFrom0xArtifactAsync(
+            artifacts.DummyERC721Receiver,
+            provider,
+            txDefaults,
+        );
     });
     beforeEach(async () => {
         await blockchainLifecycle.startAsync();
@@ -79,14 +94,14 @@ describe('Asset Transfer Proxies', () => {
     describe('Transfer Proxy - ERC20', () => {
         describe('transferFrom', () => {
             it('should successfully transfer tokens', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(10);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -105,14 +120,14 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should do nothing if transferring 0 amount of a token', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(0);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -131,8 +146,8 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if allowances are too low', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 // Create allowance less than transfer amount. Set allowance on proxy.
                 const allowance = new BigNumber(0);
                 const transferAmount = new BigNumber(10);
@@ -145,7 +160,7 @@ describe('Asset Transfer Proxies', () => {
                 // Perform a transfer; expect this to fail.
                 return expectRevertOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         transferAmount,
@@ -155,20 +170,14 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if requesting address is not authorized', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(10);
                 return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        {
-                            from: notAuthorized,
-                        },
-                    ),
+                    erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
+                        from: notAuthorized,
+                    }),
                 );
             });
         });
@@ -177,16 +186,16 @@ describe('Asset Transfer Proxies', () => {
             it('should succesfully make multiple token transfers', async () => {
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
 
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 const amount = new BigNumber(10);
                 const numTransfers = 2;
-                const assetMetadata = _.times(numTransfers, () => encodedProxyMetadata);
+                const assetData = _.times(numTransfers, () => encodedAssetData);
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => amount);
 
                 const txHash = await erc20Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetMetadata,
+                    assetData,
                     fromAddresses,
                     toAddresses,
                     amounts,
@@ -208,22 +217,18 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if not called by an authorized address', async () => {
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 const amount = new BigNumber(10);
                 const numTransfers = 2;
-                const assetMetadata = _.times(numTransfers, () => encodedProxyMetadata);
+                const assetData = _.times(numTransfers, () => encodedAssetData);
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => amount);
 
                 return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.batchTransferFrom.sendTransactionAsync(
-                        assetMetadata,
-                        fromAddresses,
-                        toAddresses,
-                        amounts,
-                        { from: notAuthorized },
-                    ),
+                    erc20Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                        from: notAuthorized,
+                    }),
                 );
             });
         });
@@ -237,11 +242,8 @@ describe('Asset Transfer Proxies', () => {
     describe('Transfer Proxy - ERC721', () => {
         describe('transferFrom', () => {
             it('should successfully transfer tokens', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
@@ -249,7 +251,7 @@ describe('Asset Transfer Proxies', () => {
                 const amount = new BigNumber(1);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -262,12 +264,94 @@ describe('Asset Transfer Proxies', () => {
                 expect(newOwnerMakerAsset).to.be.bignumber.equal(takerAddress);
             });
 
-            it('should throw if transferring 0 amount of a token', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
+            it('should not call onERC721Received when transferring to a smart contract without receiver data', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                // Verify pre-condition
+                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
+                // Perform a transfer from makerAddress to takerAddress
+                const amount = new BigNumber(1);
+                const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
+                    encodedAssetData,
+                    makerAddress,
+                    erc721Receiver.address,
+                    amount,
+                    { from: exchangeAddress },
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
+                // Parse transaction logs
+                const logDecoder = new LogDecoder(web3Wrapper, erc721Receiver.address);
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(txHash);
+                // Verify that no log was emitted by erc721 receiver
+                expect(tx.logs.length).to.be.equal(0);
+                // Verify transfer was successful
+                const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(newOwnerMakerAsset).to.be.bignumber.equal(erc721Receiver.address);
+            });
+
+            it('should call onERC721Received when transferring to a smart contract with receiver data', async () => {
+                // Construct ERC721 asset data
+                const receiverData = ethUtil.bufferToHex(assetProxyUtils.encodeUint256(generatePseudoRandomSalt()));
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(
+                    erc721Token.address,
+                    erc721MakerTokenId,
+                    receiverData,
+                );
+                // Verify pre-condition
+                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
+                // Perform a transfer from makerAddress to takerAddress
+                const amount = new BigNumber(1);
+                const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
+                    encodedAssetData,
+                    makerAddress,
+                    erc721Receiver.address,
+                    amount,
+                    { from: exchangeAddress },
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
+                // Parse transaction logs
+                const logDecoder = new LogDecoder(web3Wrapper, erc721Receiver.address);
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(txHash);
+                // Validate log emitted by erc721 receiver
+                expect(tx.logs.length).to.be.equal(1);
+                const tokenReceivedLog = tx.logs[0] as LogWithDecodedArgs<TokenReceivedContractEventArgs>;
+                expect(tokenReceivedLog.args.from).to.be.equal(makerAddress);
+                expect(tokenReceivedLog.args.tokenId).to.be.bignumber.equal(erc721MakerTokenId);
+                expect(tokenReceivedLog.args.data).to.be.equal(receiverData);
+                // Verify transfer was successful
+                const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(newOwnerMakerAsset).to.be.bignumber.equal(erc721Receiver.address);
+            });
+
+            it('should throw if there is receiver data but contract does not have onERC721Received', async () => {
+                // Construct ERC721 asset data
+                const receiverData = ethUtil.bufferToHex(assetProxyUtils.encodeUint256(generatePseudoRandomSalt()));
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(
                     erc721Token.address,
                     erc721MakerTokenId,
+                    receiverData,
+                );
+                // Verify pre-condition
+                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
+                // Perform a transfer from makerAddress to takerAddress
+                const amount = new BigNumber(1);
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    erc721Proxy.transferFrom.sendTransactionAsync(
+                        encodedAssetData,
+                        makerAddress,
+                        erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
+                        amount,
+                        { from: exchangeAddress },
+                    ),
                 );
+            });
+
+            it('should throw if transferring 0 amount of a token', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
@@ -275,7 +359,7 @@ describe('Asset Transfer Proxies', () => {
                 const amount = new BigNumber(0);
                 return expectRevertOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -285,11 +369,8 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if transferring > 1 amount of a token', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
@@ -297,7 +378,7 @@ describe('Asset Transfer Proxies', () => {
                 const amount = new BigNumber(500);
                 return expectRevertOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -307,11 +388,8 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if allowances are too low', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Remove transfer approval for makerAddress.
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, false, {
@@ -322,29 +400,20 @@ describe('Asset Transfer Proxies', () => {
                 // Perform a transfer; expect this to fail.
                 const amount = new BigNumber(1);
                 return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        {
-                            from: notAuthorized,
-                        },
-                    ),
+                    erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
+                        from: notAuthorized,
+                    }),
                 );
             });
 
             it('should throw if requesting address is not authorized', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
                 return expectRevertOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -360,16 +429,16 @@ describe('Asset Transfer Proxies', () => {
                 const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
 
                 const numTransfers = 2;
-                const assetMetadata = [
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdA),
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdB),
+                const assetData = [
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA),
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB),
                 ];
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => new BigNumber(1));
 
                 const txHash = await erc721Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetMetadata,
+                    assetData,
                     fromAddresses,
                     toAddresses,
                     amounts,
@@ -392,22 +461,18 @@ describe('Asset Transfer Proxies', () => {
                 const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
 
                 const numTransfers = 2;
-                const assetMetadata = [
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdA),
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdB),
+                const assetData = [
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA),
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB),
                 ];
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => new BigNumber(1));
 
                 return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.batchTransferFrom.sendTransactionAsync(
-                        assetMetadata,
-                        fromAddresses,
-                        toAddresses,
-                        amounts,
-                        { from: notAuthorized },
-                    ),
+                    erc721Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                        from: notAuthorized,
+                    }),
                 );
             });
         });
@@ -418,3 +483,4 @@ describe('Asset Transfer Proxies', () => {
         });
     });
 });
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index bee74cca8..53b98c755 100644
--- a/packages/contracts/test/exchange/core.ts
+++ b/packages/contracts/test/exchange/core.ts
@@ -87,7 +87,7 @@ describe('Exchange core', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -114,8 +114,8 @@ describe('Exchange core', () => {
             exchangeAddress: exchange.address,
             makerAddress,
             feeRecipientAddress,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerAssetAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerAssetAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
@@ -711,8 +711,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -737,8 +737,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -759,8 +759,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -781,8 +781,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(2),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -803,8 +803,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(500),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -825,8 +825,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(0),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -846,8 +846,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -886,8 +886,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: new BigNumber(1),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
             });
             // Verify pre-conditions
             const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
diff --git a/packages/contracts/test/exchange/dispatcher.ts b/packages/contracts/test/exchange/dispatcher.ts
index 02d43a132..9e113e47d 100644
--- a/packages/contracts/test/exchange/dispatcher.ts
+++ b/packages/contracts/test/exchange/dispatcher.ts
@@ -275,13 +275,13 @@ describe('AssetProxyDispatcher', () => {
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             // Construct metadata for ERC20 proxy
-            const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+            const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
             // Perform a transfer from makerAddress to takerAddress
             const erc20Balances = await erc20Wrapper.getBalancesAsync();
             const amount = new BigNumber(10);
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedProxyMetadata,
+                    encodedAssetData,
                     makerAddress,
                     takerAddress,
                     amount,
@@ -301,12 +301,12 @@ describe('AssetProxyDispatcher', () => {
 
         it('should throw if dispatching to unregistered proxy', async () => {
             // Construct metadata for ERC20 proxy
-            const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+            const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
             // Perform a transfer from makerAddress to takerAddress
             const amount = new BigNumber(10);
             return expectRevertOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedProxyMetadata,
+                    encodedAssetData,
                     makerAddress,
                     takerAddress,
                     amount,
diff --git a/packages/contracts/test/exchange/libs.ts b/packages/contracts/test/exchange/libs.ts
index b12934014..eff05981d 100644
--- a/packages/contracts/test/exchange/libs.ts
+++ b/packages/contracts/test/exchange/libs.ts
@@ -38,8 +38,8 @@ describe('Exchange libs', () => {
             exchangeAddress: libs.address,
             makerAddress,
             feeRecipientAddress: addressUtils.generatePseudoRandomAddress(),
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
diff --git a/packages/contracts/test/exchange/match_orders.ts b/packages/contracts/test/exchange/match_orders.ts
index aab3308ae..18a46187f 100644
--- a/packages/contracts/test/exchange/match_orders.ts
+++ b/packages/contracts/test/exchange/match_orders.ts
@@ -96,7 +96,7 @@ describe('matchOrders', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -122,8 +122,8 @@ describe('matchOrders', () => {
         const defaultOrderParams = {
             ...constants.STATIC_ORDER_PARAMS,
             exchangeAddress: exchange.address,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
         };
         const privateKeyLeft = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddressLeft)];
         orderFactoryLeft = new OrderFactory(privateKeyLeft, defaultOrderParams);
@@ -148,16 +148,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -182,16 +180,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -227,16 +223,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(20), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(4), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -261,16 +255,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -295,16 +287,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -334,8 +324,8 @@ describe('matchOrders', () => {
             //       branch in the contract twice for this test.
             const signedOrderRight2 = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -364,8 +354,6 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
@@ -373,8 +361,8 @@ describe('matchOrders', () => {
 
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -404,8 +392,6 @@ describe('matchOrders', () => {
             //       branch in the contract twice for this test.
             const signedOrderLeft2 = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
@@ -437,16 +423,14 @@ describe('matchOrders', () => {
             const feeRecipientAddress = feeRecipientAddressLeft;
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress,
@@ -465,16 +449,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -494,16 +476,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -523,16 +503,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -552,16 +530,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -581,16 +557,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: makerAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: makerAddressRight,
@@ -609,16 +583,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -635,16 +607,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -661,16 +631,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -691,16 +659,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -721,16 +687,16 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -752,16 +718,16 @@ describe('matchOrders', () => {
             const erc721TokenToTransfer = erc721LeftMakerAssetIds[0];
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: new BigNumber(1),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -787,16 +753,16 @@ describe('matchOrders', () => {
             const erc721TokenToTransfer = erc721RightMakerAssetIds[0];
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: new BigNumber(1),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
diff --git a/packages/contracts/test/exchange/signature_validator.ts b/packages/contracts/test/exchange/signature_validator.ts
index 79db620b4..c39fd6ee4 100644
--- a/packages/contracts/test/exchange/signature_validator.ts
+++ b/packages/contracts/test/exchange/signature_validator.ts
@@ -42,8 +42,8 @@ describe('MixinSignatureValidator', () => {
             exchangeAddress: signatureValidator.address,
             makerAddress,
             feeRecipientAddress: addressUtils.generatePseudoRandomAddress(),
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
diff --git a/packages/contracts/test/exchange/transactions.ts b/packages/contracts/test/exchange/transactions.ts
index 7897fa558..12390ce01 100644
--- a/packages/contracts/test/exchange/transactions.ts
+++ b/packages/contracts/test/exchange/transactions.ts
@@ -72,7 +72,7 @@ describe('Exchange transactions', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -91,8 +91,8 @@ describe('Exchange transactions', () => {
             exchangeAddress: exchange.address,
             makerAddress,
             feeRecipientAddress,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerTokenAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerTokenAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerTokenAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerTokenAddress),
         };
         makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         takerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(takerAddress)];
@@ -224,8 +224,8 @@ describe('Exchange transactions', () => {
                 exchangeAddress: exchange.address,
                 makerAddress,
                 feeRecipientAddress,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerTokenAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerTokenAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerTokenAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerTokenAddress),
             };
             whitelistOrderFactory = new OrderFactory(makerPrivateKey, defaultOrderParams);
         });
diff --git a/packages/contracts/test/exchange/wrapper.ts b/packages/contracts/test/exchange/wrapper.ts
index 258e1ff81..b66cff90a 100644
--- a/packages/contracts/test/exchange/wrapper.ts
+++ b/packages/contracts/test/exchange/wrapper.ts
@@ -81,7 +81,7 @@ describe('Exchange wrappers', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -108,8 +108,8 @@ describe('Exchange wrappers', () => {
             exchangeAddress: exchange.address,
             makerAddress,
             feeRecipientAddress,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerAssetAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerAssetAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
@@ -304,7 +304,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: makerZRXBalance,
                 makerFee: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -316,7 +316,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(makerZRXAllowance),
                 makerFee: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -328,7 +328,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: takerZRXBalance,
                 takerFee: new BigNumber(1),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -340,7 +340,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: new BigNumber(takerZRXAllowance),
                 takerFee: new BigNumber(1),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -354,8 +354,8 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -692,7 +692,7 @@ describe('Exchange wrappers', () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
                     orderFactory.newSignedOrder(),
                 ];
@@ -785,7 +785,7 @@ describe('Exchange wrappers', () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
                     orderFactory.newSignedOrder(),
                 ];
@@ -874,7 +874,7 @@ describe('Exchange wrappers', () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
                     orderFactory.newSignedOrder(),
                 ];
@@ -967,7 +967,7 @@ describe('Exchange wrappers', () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
                     orderFactory.newSignedOrder(),
                 ];
diff --git a/packages/contracts/test/libraries/lib_bytes.ts b/packages/contracts/test/libraries/lib_bytes.ts
index 0996cdc84..2fefb7aeb 100644
--- a/packages/contracts/test/libraries/lib_bytes.ts
+++ b/packages/contracts/test/libraries/lib_bytes.ts
@@ -1,4 +1,5 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
 import { BigNumber } from '@0xproject/utils';
 import BN = require('bn.js');
 import * as chai from 'chai';
@@ -28,6 +29,15 @@ describe('LibBytes', () => {
     let testAddress: string;
     const testBytes32 = '0x102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f01020';
     const testUint256 = new BigNumber(testBytes32, 16);
+    let shortData: string;
+    let shortTestBytes: string;
+    let shortTestBytesAsBuffer: Buffer;
+    let wordOfData: string;
+    let wordOfTestBytes: string;
+    let wordOfTestBytesAsBuffer: Buffer;
+    let longData: string;
+    let longTestBytes: string;
+    let longTestBytesAsBuffer: Buffer;
 
     before(async () => {
         await blockchainLifecycle.startAsync();
@@ -48,6 +58,26 @@ describe('LibBytes', () => {
         expect(byteArrayLongerThan32BytesLength).to.be.greaterThan(32);
         const testBytes32Length = ethUtil.toBuffer(testBytes32).byteLength;
         expect(testBytes32Length).to.be.equal(32);
+        // Create short test bytes
+        shortData = '0xffffaa';
+        const encodedShortData = ethUtil.toBuffer(shortData);
+        const shortDataLength = new BigNumber(encodedShortData.byteLength);
+        const encodedShortDataLength = assetProxyUtils.encodeUint256(shortDataLength);
+        shortTestBytesAsBuffer = Buffer.concat([encodedShortDataLength, encodedShortData]);
+        shortTestBytes = ethUtil.bufferToHex(shortTestBytesAsBuffer);
+        // Create test bytes one word in length
+        wordOfData = ethUtil.bufferToHex(assetProxyUtils.encodeUint256(generatePseudoRandomSalt()));
+        const encodedWordOfData = ethUtil.toBuffer(wordOfData);
+        const wordOfDataLength = new BigNumber(encodedWordOfData.byteLength);
+        const encodedWordOfDataLength = assetProxyUtils.encodeUint256(wordOfDataLength);
+        wordOfTestBytesAsBuffer = Buffer.concat([encodedWordOfDataLength, encodedWordOfData]);
+        wordOfTestBytes = ethUtil.bufferToHex(wordOfTestBytesAsBuffer);
+        // Create long test bytes (combines short test bytes with word of test bytes)
+        longData = ethUtil.bufferToHex(Buffer.concat([encodedShortData, encodedWordOfData]));
+        const longDataLength = new BigNumber(encodedShortData.byteLength + encodedWordOfData.byteLength);
+        const encodedLongDataLength = assetProxyUtils.encodeUint256(longDataLength);
+        longTestBytesAsBuffer = Buffer.concat([encodedLongDataLength, encodedShortData, encodedWordOfData]);
+        longTestBytes = ethUtil.bufferToHex(longTestBytesAsBuffer);
     });
     beforeEach(async () => {
         await blockchainLifecycle.startAsync();
@@ -60,7 +90,7 @@ describe('LibBytes', () => {
         it('should revert if length is 0', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopByte.callAsync(constants.NULL_BYTES),
-                constants.LIB_BYTES_GT_ZERO_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED,
             );
         });
 
@@ -77,7 +107,7 @@ describe('LibBytes', () => {
         it('should revert if length is less than 20', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopAddress.callAsync(byteArrayShorterThan20Bytes),
-                constants.LIB_BYTES_GTE_20_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
             );
         });
 
@@ -163,7 +193,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(shortByteArray, offset),
-                constants.LIB_BYTES_GTE_20_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
             );
         });
 
@@ -172,7 +202,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GTE_20_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
             );
         });
     });
@@ -209,7 +239,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GTE_32_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
 
@@ -217,7 +247,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GTE_32_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
     });
@@ -258,7 +288,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GTE_32_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
 
@@ -269,7 +299,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(testUint256AsBuffer.byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GTE_32_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
     });
@@ -291,7 +321,7 @@ describe('LibBytes', () => {
             const byteArrayLessThan4Bytes = '0x010101';
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadFirst4.callAsync(byteArrayLessThan4Bytes),
-                constants.LIB_BYTES_GTE_4_LENGTH_REQUIRED,
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED,
             );
         });
         it('should return the first 4 bytes of a byte array of arbitrary length', async () => {
@@ -300,4 +330,180 @@ describe('LibBytes', () => {
             expect(first4Bytes).to.equal(expectedFirst4Bytes);
         });
     });
+
+    describe('readBytes', () => {
+        it('should successfully read short, nested array of bytes when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const bytes = await libBytes.publicReadBytes.callAsync(shortTestBytes, testBytesOffset);
+            return expect(bytes).to.be.equal(shortData);
+        });
+
+        it('should successfully read short, nested array of bytes when it is offset in the array', async () => {
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, shortTestBytesAsBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes = await libBytes.publicReadBytes.callAsync(combinedByteArray, testUint256Offset);
+            return expect(bytes).to.be.equal(shortData);
+        });
+
+        it('should successfully read a nested array of bytes - one word in length - when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const bytes = await libBytes.publicReadBytes.callAsync(wordOfTestBytes, testBytesOffset);
+            return expect(bytes).to.be.equal(wordOfData);
+        });
+
+        it('should successfully read a nested array of bytes - one word in length - when it is offset in the array', async () => {
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, wordOfTestBytesAsBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes = await libBytes.publicReadBytes.callAsync(combinedByteArray, testUint256Offset);
+            return expect(bytes).to.be.equal(wordOfData);
+        });
+
+        it('should successfully read long, nested array of bytes when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const bytes = await libBytes.publicReadBytes.callAsync(longTestBytes, testBytesOffset);
+            return expect(bytes).to.be.equal(longData);
+        });
+
+        it('should successfully read long, nested array of bytes when it is offset in the array', async () => {
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, longTestBytesAsBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes = await libBytes.publicReadBytes.callAsync(combinedByteArray, testUint256Offset);
+            return expect(bytes).to.be.equal(longData);
+        });
+
+        it('should fail if the byte array is too short to hold the length of a nested byte array', async () => {
+            // The length of the nested array is 32 bytes. By storing less than 32 bytes, a length cannot be read.
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(byteArrayShorterThan32Bytes, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+
+        it('should fail if we store a nested byte array length, without a nested byte array', async () => {
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(testBytes32, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+            );
+        });
+
+        it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array', async () => {
+            const badOffset = new BigNumber(ethUtil.toBuffer(byteArrayShorterThan32Bytes).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(byteArrayShorterThan32Bytes, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+
+        it('should fail if the length between the offset and end of the byte array is too short to hold the nested byte array', async () => {
+            const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(testBytes32, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+    });
+
+    describe('writeBytes', () => {
+        it('should successfully write short, nested array of bytes when it takes up the whole array)', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(shortTestBytesAsBuffer.byteLength));
+            const bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, testBytesOffset, shortData);
+            const bytesRead = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytesRead).to.be.equal(shortData);
+        });
+
+        it('should successfully write short, nested array of bytes when it is offset in the array', async () => {
+            // Write a prefix to the array
+            const prefixData = '0xabcdef';
+            const prefixDataAsBuffer = ethUtil.toBuffer(prefixData);
+            const prefixOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(
+                new Buffer(prefixDataAsBuffer.byteLength + shortTestBytesAsBuffer.byteLength),
+            );
+            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            // Write data after prefix
+            const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
+            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, shortData);
+            // Read data after prefix and validate
+            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytes).to.be.equal(shortData);
+        });
+
+        it('should successfully write a nested array of bytes - one word in length - when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(wordOfTestBytesAsBuffer.byteLength));
+            const bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, testBytesOffset, wordOfData);
+            const bytesRead = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytesRead).to.be.equal(wordOfData);
+        });
+
+        it('should successfully write a nested array of bytes - one word in length - when it is offset in the array', async () => {
+            // Write a prefix to the array
+            const prefixData = '0xabcdef';
+            const prefixDataAsBuffer = ethUtil.toBuffer(prefixData);
+            const prefixOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(
+                new Buffer(prefixDataAsBuffer.byteLength + wordOfTestBytesAsBuffer.byteLength),
+            );
+            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            // Write data after prefix
+            const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
+            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, wordOfData);
+            // Read data after prefix and validate
+            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytes).to.be.equal(wordOfData);
+        });
+
+        it('should successfully write a long, nested bytes when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(longTestBytesAsBuffer.byteLength));
+            const bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, testBytesOffset, longData);
+            const bytesRead = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytesRead).to.be.equal(longData);
+        });
+
+        it('should successfully write long, nested array of bytes when it is offset in the array', async () => {
+            // Write a prefix to the array
+            const prefixData = '0xabcdef';
+            const prefixDataAsBuffer = ethUtil.toBuffer(prefixData);
+            const prefixOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(
+                new Buffer(prefixDataAsBuffer.byteLength + longTestBytesAsBuffer.byteLength),
+            );
+            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            // Write data after prefix
+            const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
+            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, longData);
+            // Read data after prefix and validate
+            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytes).to.be.equal(longData);
+        });
+
+        it('should fail if the byte array is too short to hold the length of a nested byte array', async () => {
+            const offset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(1));
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteBytes.callAsync(emptyByteArray, offset, longData),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+            );
+        });
+
+        it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array)', async () => {
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(shortTestBytesAsBuffer.byteLength));
+            const badOffset = new BigNumber(ethUtil.toBuffer(shortTestBytesAsBuffer).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteBytes.callAsync(emptyByteArray, badOffset, shortData),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+            );
+        });
+    });
 });
+// tslint:disable:max-file-line-count
diff --git a/packages/contracts/test/libraries/lib_mem.ts b/packages/contracts/test/libraries/lib_mem.ts
new file mode 100644
index 000000000..90d54edcb
--- /dev/null
+++ b/packages/contracts/test/libraries/lib_mem.ts
@@ -0,0 +1,190 @@
+import { BigNumber } from '@0xproject/utils';
+import * as chai from 'chai';
+
+import { TestLibMemContract } from '../../src/generated_contract_wrappers/test_lib_mem';
+import { artifacts } from '../../src/utils/artifacts';
+import { chaiSetup } from '../../src/utils/chai_setup';
+import { provider, txDefaults } from '../../src/utils/web3_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+// BUG: Ideally we would use Buffer.from(memory).toString('hex')
+// https://github.com/Microsoft/TypeScript/issues/23155
+const toHex = (buf: Uint8Array): string => buf.reduce((a, v) => a + ('00' + v.toString(16)).slice(-2), '0x');
+
+const fromHex = (str: string): Uint8Array => Uint8Array.from(Buffer.from(str.slice(2), 'hex'));
+
+describe('LibMem', () => {
+    let testLibMem: TestLibMemContract;
+
+    before(async () => {
+        // Deploy TestLibMem
+        testLibMem = await TestLibMemContract.deployFrom0xArtifactAsync(artifacts.TestLibMem, provider, txDefaults);
+    });
+
+    describe('memCopy', () => {
+        // Create memory 0x000102...FF
+        const memSize = 256;
+        const memory = new Uint8Array(memSize).map((_, i) => i);
+        const memHex = toHex(memory);
+
+        // Reference implementation to test against
+        const refMemcpy = (mem: Uint8Array, dest: number, source: number, length: number): Uint8Array =>
+            Uint8Array.from(memory).copyWithin(dest, source, source + length);
+
+        // Test vectors: destination, source, length, job description
+        type Tests = Array<[number, number, number, string]>;
+
+        const test = (tests: Tests) =>
+            tests.forEach(([dest, source, length, job]) =>
+                it(job, async () => {
+                    const expected = refMemcpy(memory, dest, source, length);
+                    const resultStr = await testLibMem.testMemcpy.callAsync(
+                        memHex,
+                        new BigNumber(dest),
+                        new BigNumber(source),
+                        new BigNumber(length),
+                    );
+                    const result = fromHex(resultStr);
+                    expect(result).to.deep.equal(expected);
+                }),
+            );
+
+        test([[0, 0, 0, 'copies zero bytes with overlap']]);
+
+        describe('copies forward', () =>
+            test([
+                [128, 0, 0, 'zero bytes'],
+                [128, 0, 1, 'one byte'],
+                [128, 0, 11, 'eleven bytes'],
+                [128, 0, 31, 'thirty-one bytes'],
+                [128, 0, 32, 'one word'],
+                [128, 0, 64, 'two words'],
+                [128, 0, 96, 'three words'],
+                [128, 0, 33, 'one word and one byte'],
+                [128, 0, 72, 'two words and eight bytes'],
+                [128, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word', () =>
+            test([
+                [16, 0, 0, 'zero bytes'],
+                [16, 0, 1, 'one byte'],
+                [16, 0, 11, 'eleven bytes'],
+                [16, 0, 16, 'sixteen bytes'],
+            ]));
+
+        describe('copies forward with one byte overlap', () =>
+            test([
+                [0, 0, 1, 'one byte'],
+                [10, 0, 11, 'eleven bytes'],
+                [30, 0, 31, 'thirty-one bytes'],
+                [31, 0, 32, 'one word'],
+                [32, 0, 33, 'one word and one byte'],
+                [71, 0, 72, 'two words and eight bytes'],
+                [99, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with thirty-one bytes overlap', () =>
+            test([
+                [0, 0, 31, 'thirty-one bytes'],
+                [1, 0, 32, 'one word'],
+                [2, 0, 33, 'one word and one byte'],
+                [41, 0, 72, 'two words and eight bytes'],
+                [69, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with one word overlap', () =>
+            test([
+                [0, 0, 32, 'one word'],
+                [1, 0, 33, 'one word and one byte'],
+                [41, 0, 72, 'two words and eight bytes'],
+                [69, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with one word and one byte overlap', () =>
+            test([
+                [0, 0, 33, 'one word and one byte'],
+                [40, 0, 72, 'two words and eight bytes'],
+                [68, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with two words overlap', () =>
+            test([
+                [0, 0, 64, 'two words'],
+                [8, 0, 72, 'two words and eight bytes'],
+                [36, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word and one byte overlap', () =>
+            test([[0, 0, 1, 'one byte'], [10, 0, 11, 'eleven bytes'], [15, 0, 16, 'sixteen bytes']]));
+
+        describe('copies backward', () =>
+            test([
+                [0, 128, 0, 'zero bytes'],
+                [0, 128, 1, 'one byte'],
+                [0, 128, 11, 'eleven bytes'],
+                [0, 128, 31, 'thirty-one bytes'],
+                [0, 128, 32, 'one word'],
+                [0, 128, 64, 'two words'],
+                [0, 128, 96, 'three words'],
+                [0, 128, 33, 'one word and one byte'],
+                [0, 128, 72, 'two words and eight bytes'],
+                [0, 128, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward within one word', () =>
+            test([
+                [0, 16, 0, 'zero bytes'],
+                [0, 16, 1, 'one byte'],
+                [0, 16, 11, 'eleven bytes'],
+                [0, 16, 16, 'sixteen bytes'],
+            ]));
+
+        describe('copies backward with one byte overlap', () =>
+            test([
+                [0, 0, 1, 'one byte'],
+                [0, 10, 11, 'eleven bytes'],
+                [0, 30, 31, 'thirty-one bytes'],
+                [0, 31, 32, 'one word'],
+                [0, 32, 33, 'one word and one byte'],
+                [0, 71, 72, 'two words and eight bytes'],
+                [0, 99, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with thirty-one bytes overlap', () =>
+            test([
+                [0, 0, 31, 'thirty-one bytes'],
+                [0, 1, 32, 'one word'],
+                [0, 2, 33, 'one word and one byte'],
+                [0, 41, 72, 'two words and eight bytes'],
+                [0, 69, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with one word overlap', () =>
+            test([
+                [0, 0, 32, 'one word'],
+                [0, 1, 33, 'one word and one byte'],
+                [0, 41, 72, 'two words and eight bytes'],
+                [0, 69, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with one word and one byte overlap', () =>
+            test([
+                [0, 0, 33, 'one word and one byte'],
+                [0, 40, 72, 'two words and eight bytes'],
+                [0, 68, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with two words overlap', () =>
+            test([
+                [0, 0, 64, 'two words'],
+                [0, 8, 72, 'two words and eight bytes'],
+                [0, 36, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word and one byte overlap', () =>
+            test([[0, 0, 1, 'one byte'], [0, 10, 11, 'eleven bytes'], [0, 15, 16, 'sixteen bytes']]));
+    });
+});
diff --git a/packages/fill-scenarios/src/index.ts b/packages/fill-scenarios/src/index.ts
index dc877a0fd..038826af2 100644
--- a/packages/fill-scenarios/src/index.ts
+++ b/packages/fill-scenarios/src/index.ts
@@ -169,10 +169,10 @@ export class FillScenarios {
         feeRecepientAddress: string,
         expirationTimeSeconds?: BigNumber,
     ): Promise<SignedOrder> {
-        const makerERC20ProxyData = assetProxyUtils.decodeERC20ProxyData(makerAssetData);
-        const makerTokenAddress = makerERC20ProxyData.tokenAddress;
-        const takerERC20ProxyData = assetProxyUtils.decodeERC20ProxyData(takerAssetData);
-        const takerTokenAddress = takerERC20ProxyData.tokenAddress;
+        const makerERC20AssetData = assetProxyUtils.decodeERC20AssetData(makerAssetData);
+        const makerTokenAddress = makerERC20AssetData.tokenAddress;
+        const takerERC20AssetData = assetProxyUtils.decodeERC20AssetData(takerAssetData);
+        const takerTokenAddress = takerERC20AssetData.tokenAddress;
         await Promise.all([
             this._increaseERC20BalanceAndAllowanceAsync(makerTokenAddress, makerAddress, makerFillableAmount),
             this._increaseERC20BalanceAndAllowanceAsync(takerTokenAddress, takerAddress, takerFillableAmount),
diff --git a/packages/migrations/artifacts/2.0.0/TestLibAssetProxyDecoder.json b/packages/migrations/artifacts/2.0.0/TestLibAssetProxyDecoder.json
new file mode 100644
index 000000000..40790e39f
--- /dev/null
+++ b/packages/migrations/artifacts/2.0.0/TestLibAssetProxyDecoder.json
@@ -0,0 +1,119 @@
+{
+	"schemaVersion": "2.0.0",
+	"contractName": "TestLibAssetProxyDecoder",
+	"compilerOutput": {
+		"abi": [
+			{
+				"constant": true,
+				"inputs": [
+					{
+						"name": "proxyData",
+						"type": "bytes"
+					}
+				],
+				"name": "publicDecodeERC721Data",
+				"outputs": [
+					{
+						"name": "",
+						"type": "uint8"
+					},
+					{
+						"name": "",
+						"type": "address"
+					},
+					{
+						"name": "",
+						"type": "uint256"
+					},
+					{
+						"name": "",
+						"type": "bytes"
+					}
+				],
+				"payable": false,
+				"stateMutability": "pure",
+				"type": "function"
+			},
+			{
+				"constant": true,
+				"inputs": [
+					{
+						"name": "proxyData",
+						"type": "bytes"
+					}
+				],
+				"name": "publicDecodeERC20Data",
+				"outputs": [
+					{
+						"name": "",
+						"type": "uint8"
+					},
+					{
+						"name": "",
+						"type": "address"
+					}
+				],
+				"payable": false,
+				"stateMutability": "pure",
+				"type": "function"
+			}
+		],
+		"evm": {
+			"bytecode": {
+				"linkReferences": {},
+				"object": "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",
+				"opcodes": "PUSH1 0x80 PUSH1 0x40 MSTORE CALLVALUE DUP1 ISZERO PUSH2 0x10 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0x791 DUP1 PUSH2 0x20 PUSH1 0x0 CODECOPY PUSH1 0x0 RETURN STOP PUSH1 0x80 PUSH1 0x40 MSTORE PUSH1 0x4 CALLDATASIZE LT PUSH2 0x32 JUMPI PUSH4 0xFFFFFFFF PUSH1 0xE0 PUSH1 0x2 EXP PUSH1 0x0 CALLDATALOAD DIV AND PUSH4 0x72C2F527 DUP2 EQ PUSH2 0x37 JUMPI DUP1 PUSH4 0xBD27C22D EQ PUSH2 0x70 JUMPI JUMPDEST PUSH1 0x0 DUP1 REVERT JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0x43 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0x57 PUSH2 0x52 CALLDATASIZE PUSH1 0x4 PUSH2 0x58C JUMP JUMPDEST PUSH2 0x9E JUMP JUMPDEST PUSH1 0x40 MLOAD PUSH2 0x67 SWAP5 SWAP4 SWAP3 SWAP2 SWAP1 PUSH2 0x64A JUMP JUMPDEST PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 RETURN JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0x7C JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0x90 PUSH2 0x8B CALLDATASIZE PUSH1 0x4 PUSH2 0x58C JUMP JUMPDEST PUSH2 0xBD JUMP JUMPDEST PUSH1 0x40 MLOAD PUSH2 0x67 SWAP3 SWAP2 SWAP1 PUSH2 0x62F JUMP JUMPDEST PUSH1 0x0 DUP1 PUSH1 0x0 PUSH1 0x60 PUSH2 0xAE DUP6 PUSH2 0xD2 JUMP JUMPDEST SWAP4 POP SWAP4 POP SWAP4 POP SWAP4 POP SWAP2 SWAP4 POP SWAP2 SWAP4 JUMP JUMPDEST PUSH1 0x0 DUP1 PUSH2 0xC9 DUP4 PUSH2 0x1B5 JUMP JUMPDEST SWAP2 POP SWAP2 POP SWAP2 POP SWAP2 JUMP JUMPDEST PUSH1 0x0 DUP1 PUSH1 0x0 PUSH1 0x60 PUSH1 0x35 DUP6 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH32 0x4D65746164617461206D75737420686176652061206C656E677468206F662061 DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x3A103632B0B9BA101A9997 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x159 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 REVERT JUMPDEST POP DUP5 PUSH1 0x0 DUP2 MLOAD DUP2 LT ISZERO ISZERO PUSH2 0x169 JUMPI INVALID JUMPDEST ADD PUSH1 0x20 ADD MLOAD PUSH1 0xF8 PUSH1 0x2 EXP SWAP1 DUP2 SWAP1 DIV DUP2 MUL DIV SWAP4 POP PUSH2 0x187 DUP6 PUSH1 0x1 PUSH2 0x25A JUMP JUMPDEST SWAP3 POP PUSH2 0x194 DUP6 PUSH1 0x15 PUSH2 0x2D6 JUMP JUMPDEST SWAP2 POP PUSH1 0x35 DUP6 MLOAD GT ISZERO PUSH2 0x1AE JUMPI PUSH2 0x1AB DUP6 PUSH1 0x35 PUSH2 0x2E9 JUMP JUMPDEST SWAP1 POP JUMPDEST SWAP2 SWAP4 POP SWAP2 SWAP4 JUMP JUMPDEST PUSH1 0x0 DUP1 DUP3 MLOAD PUSH1 0x15 EQ PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x22 DUP2 MSTORE PUSH1 0x20 ADD PUSH32 0x4D65746164617461206D75737420686176652061206C656E677468206F662032 DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xF1 PUSH1 0x2 EXP PUSH2 0x1897 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x225 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP DUP3 PUSH1 0x0 DUP2 MLOAD DUP2 LT ISZERO ISZERO PUSH2 0x235 JUMPI INVALID JUMPDEST ADD PUSH1 0x20 ADD MLOAD PUSH1 0xF8 PUSH1 0x2 EXP SWAP1 DUP2 SWAP1 DIV DUP2 MUL DIV SWAP2 POP PUSH2 0x253 DUP4 PUSH1 0x1 PUSH2 0x25A JUMP JUMPDEST SWAP1 POP SWAP2 POP SWAP2 JUMP JUMPDEST PUSH1 0x0 DUP2 PUSH1 0x14 ADD DUP4 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790191817 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x2C3 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP POP ADD PUSH1 0x14 ADD MLOAD PUSH1 0x1 PUSH1 0xA0 PUSH1 0x2 EXP SUB AND SWAP1 JUMP JUMPDEST PUSH1 0x0 PUSH2 0x2E2 DUP4 DUP4 PUSH2 0x426 JUMP JUMPDEST SWAP4 SWAP3 POP POP POP JUMP JUMPDEST PUSH1 0x60 PUSH1 0x0 DUP3 PUSH1 0x20 ADD DUP5 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790199917 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x354 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP PUSH2 0x35F DUP5 DUP5 PUSH2 0x2D6 JUMP JUMPDEST SWAP1 POP DUP1 DUP4 PUSH1 0x20 ADD ADD DUP5 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790199917 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x3CA JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP DUP1 PUSH1 0x40 MLOAD SWAP1 DUP1 DUP3 MSTORE DUP1 PUSH1 0x1F ADD PUSH1 0x1F NOT AND PUSH1 0x20 ADD DUP3 ADD PUSH1 0x40 MSTORE DUP1 ISZERO PUSH2 0x3F9 JUMPI DUP2 PUSH1 0x20 ADD PUSH1 0x20 DUP3 MUL DUP1 CODESIZE DUP4 CODECOPY ADD SWAP1 POP JUMPDEST POP SWAP2 POP PUSH2 0x41F PUSH2 0x408 DUP4 PUSH2 0x499 JUMP JUMPDEST PUSH1 0x20 ADD DUP5 PUSH2 0x415 DUP8 PUSH2 0x499 JUMP JUMPDEST ADD PUSH1 0x20 ADD DUP4 PUSH2 0x49C JUMP JUMPDEST POP SWAP3 SWAP2 POP POP JUMP JUMPDEST PUSH1 0x0 DUP2 PUSH1 0x20 ADD DUP4 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790199917 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x48F JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP POP ADD PUSH1 0x20 ADD MLOAD SWAP1 JUMP JUMPDEST SWAP1 JUMP JUMPDEST DUP1 ISZERO ISZERO PUSH2 0x4A8 JUMPI PUSH2 0x533 JUMP JUMPDEST DUP3 DUP3 EQ ISZERO PUSH2 0x4B5 JUMPI PUSH2 0x533 JUMP JUMPDEST PUSH1 0x20 PUSH1 0x1F DUP3 ADD DIV PUSH1 0x20 DUP3 MOD PUSH1 0x0 DUP2 GT ISZERO PUSH2 0x4D0 JUMPI PUSH1 0x1 DUP3 SUB SWAP2 POP JUMPDEST PUSH1 0x0 PUSH1 0x20 DUP4 MUL JUMPDEST DUP1 DUP3 LT ISZERO PUSH2 0x4F2 JUMPI DUP2 DUP7 ADD MLOAD DUP3 DUP9 ADD MSTORE PUSH1 0x20 DUP3 ADD SWAP2 POP PUSH2 0x4D7 JUMP JUMPDEST PUSH1 0x0 DUP4 GT ISZERO PUSH2 0x52E JUMPI DUP3 PUSH1 0x20 SUB PUSH1 0x8 MUL PUSH1 0x2 EXP DUP3 DUP8 ADD MLOAD DUP2 DUP3 DUP3 DIV MUL DUP6 PUSH1 0x8 MUL PUSH1 0x2 EXP DUP6 DUP12 ADD MLOAD DUP2 DUP3 DUP3 MUL DIV DUP1 DUP5 OR DUP1 DUP10 DUP16 ADD MSTORE POP POP POP POP POP POP POP JUMPDEST POP POP POP POP JUMPDEST POP POP POP JUMP JUMPDEST PUSH1 0x0 PUSH1 0x1F DUP3 ADD DUP4 SGT PUSH2 0x549 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST DUP2 CALLDATALOAD PUSH2 0x55C PUSH2 0x557 DUP3 PUSH2 0x6B4 JUMP JUMPDEST PUSH2 0x68E JUMP JUMPDEST SWAP2 POP DUP1 DUP3 MSTORE PUSH1 0x20 DUP4 ADD PUSH1 0x20 DUP4 ADD DUP6 DUP4 DUP4 ADD GT ISZERO PUSH2 0x578 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH2 0x583 DUP4 DUP3 DUP5 PUSH2 0x6F1 JUMP JUMPDEST POP POP POP SWAP3 SWAP2 POP POP JUMP JUMPDEST PUSH1 0x0 PUSH1 0x20 DUP3 DUP5 SUB SLT ISZERO PUSH2 0x59E JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST DUP2 CALLDATALOAD PUSH1 0x1 PUSH1 0x40 PUSH1 0x2 EXP SUB DUP2 GT ISZERO PUSH2 0x5B4 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH2 0x5C0 DUP5 DUP3 DUP6 ADD PUSH2 0x538 JUMP JUMPDEST SWAP5 SWAP4 POP POP POP POP JUMP JUMPDEST PUSH2 0x5D1 DUP2 PUSH2 0x6DF JUMP JUMPDEST DUP3 MSTORE POP POP JUMP JUMPDEST PUSH1 0x0 PUSH2 0x5E2 DUP3 PUSH2 0x6DB JUMP JUMPDEST DUP1 DUP5 MSTORE PUSH2 0x5F6 DUP2 PUSH1 0x20 DUP7 ADD PUSH1 0x20 DUP7 ADD PUSH2 0x6FD JUMP JUMPDEST PUSH2 0x5FF DUP2 PUSH2 0x72D JUMP JUMPDEST SWAP1 SWAP4 ADD PUSH1 0x20 ADD SWAP4 SWAP3 POP POP POP JUMP JUMPDEST PUSH2 0x5D1 DUP2 PUSH2 0x499 JUMP JUMPDEST PUSH2 0x5D1 DUP2 PUSH2 0x6EB JUMP JUMPDEST PUSH1 0x20 DUP1 DUP3 MSTORE DUP2 ADD PUSH2 0x2E2 DUP2 DUP5 PUSH2 0x5D7 JUMP JUMPDEST PUSH1 0x40 DUP2 ADD PUSH2 0x63D DUP3 DUP6 PUSH2 0x615 JUMP JUMPDEST PUSH2 0x2E2 PUSH1 0x20 DUP4 ADD DUP5 PUSH2 0x5C8 JUMP JUMPDEST PUSH1 0x80 DUP2 ADD PUSH2 0x658 DUP3 DUP8 PUSH2 0x615 JUMP JUMPDEST PUSH2 0x665 PUSH1 0x20 DUP4 ADD DUP7 PUSH2 0x5C8 JUMP JUMPDEST PUSH2 0x672 PUSH1 0x40 DUP4 ADD DUP6 PUSH2 0x60C JUMP JUMPDEST DUP2 DUP2 SUB PUSH1 0x60 DUP4 ADD MSTORE PUSH2 0x684 DUP2 DUP5 PUSH2 0x5D7 JUMP JUMPDEST SWAP7 SWAP6 POP POP POP POP POP POP JUMP JUMPDEST PUSH1 0x40 MLOAD DUP2 DUP2 ADD PUSH1 0x1 PUSH1 0x40 PUSH1 0x2 EXP SUB DUP2 GT DUP3 DUP3 LT OR ISZERO PUSH2 0x6AC JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH1 0x40 MSTORE SWAP2 SWAP1 POP JUMP JUMPDEST PUSH1 0x0 PUSH1 0x1 PUSH1 0x40 PUSH1 0x2 EXP SUB DUP3 GT ISZERO PUSH2 0x6CA JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH1 0x20 PUSH1 0x1F SWAP2 SWAP1 SWAP2 ADD PUSH1 0x1F NOT AND ADD SWAP1 JUMP JUMPDEST MLOAD SWAP1 JUMP JUMPDEST PUSH1 0x1 PUSH1 0xA0 PUSH1 0x2 EXP SUB AND SWAP1 JUMP JUMPDEST PUSH1 0xFF AND SWAP1 JUMP JUMPDEST DUP3 DUP2 DUP4 CALLDATACOPY POP PUSH1 0x0 SWAP2 ADD MSTORE JUMP JUMPDEST PUSH1 0x0 JUMPDEST DUP4 DUP2 LT ISZERO PUSH2 0x718 JUMPI DUP2 DUP2 ADD MLOAD DUP4 DUP3 ADD MSTORE PUSH1 0x20 ADD PUSH2 0x700 JUMP JUMPDEST DUP4 DUP2 GT ISZERO PUSH2 0x727 JUMPI PUSH1 0x0 DUP5 DUP5 ADD MSTORE JUMPDEST POP POP POP POP JUMP JUMPDEST PUSH1 0x1F ADD PUSH1 0x1F NOT AND SWAP1 JUMP STOP 0x4c PUSH6 0x6E677468206D PUSH22 0x73742062652067726561746572207468616E206F7220 PUSH6 0xA265627A7A72 ADDRESS PC KECCAK256 MLOAD ORIGIN 0xeb PUSH21 0x48F5B6279DEDD3C042E96FB9EA0D8A8AEA79044353 PUSH4 0x8CF00546 AND 0x5f PUSH13 0x6578706572696D656E74616CF5 STOP CALLDATACOPY ",
+				"sourceMap": "709:590:0:-;;;;8:9:-1;5:2;;;30:1;27;20:12;5:2;709:590:0;;;;;;;"
+			},
+			"deployedBytecode": {
+				"linkReferences": {},
+				"object": "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",
+				"opcodes": "PUSH1 0x80 PUSH1 0x40 MSTORE PUSH1 0x4 CALLDATASIZE LT PUSH2 0x32 JUMPI PUSH4 0xFFFFFFFF PUSH1 0xE0 PUSH1 0x2 EXP PUSH1 0x0 CALLDATALOAD DIV AND PUSH4 0x72C2F527 DUP2 EQ PUSH2 0x37 JUMPI DUP1 PUSH4 0xBD27C22D EQ PUSH2 0x70 JUMPI JUMPDEST PUSH1 0x0 DUP1 REVERT JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0x43 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0x57 PUSH2 0x52 CALLDATASIZE PUSH1 0x4 PUSH2 0x58C JUMP JUMPDEST PUSH2 0x9E JUMP JUMPDEST PUSH1 0x40 MLOAD PUSH2 0x67 SWAP5 SWAP4 SWAP3 SWAP2 SWAP1 PUSH2 0x64A JUMP JUMPDEST PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 RETURN JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0x7C JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0x90 PUSH2 0x8B CALLDATASIZE PUSH1 0x4 PUSH2 0x58C JUMP JUMPDEST PUSH2 0xBD JUMP JUMPDEST PUSH1 0x40 MLOAD PUSH2 0x67 SWAP3 SWAP2 SWAP1 PUSH2 0x62F JUMP JUMPDEST PUSH1 0x0 DUP1 PUSH1 0x0 PUSH1 0x60 PUSH2 0xAE DUP6 PUSH2 0xD2 JUMP JUMPDEST SWAP4 POP SWAP4 POP SWAP4 POP SWAP4 POP SWAP2 SWAP4 POP SWAP2 SWAP4 JUMP JUMPDEST PUSH1 0x0 DUP1 PUSH2 0xC9 DUP4 PUSH2 0x1B5 JUMP JUMPDEST SWAP2 POP SWAP2 POP SWAP2 POP SWAP2 JUMP JUMPDEST PUSH1 0x0 DUP1 PUSH1 0x0 PUSH1 0x60 PUSH1 0x35 DUP6 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH32 0x4D65746164617461206D75737420686176652061206C656E677468206F662061 DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x3A103632B0B9BA101A9997 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x159 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 REVERT JUMPDEST POP DUP5 PUSH1 0x0 DUP2 MLOAD DUP2 LT ISZERO ISZERO PUSH2 0x169 JUMPI INVALID JUMPDEST ADD PUSH1 0x20 ADD MLOAD PUSH1 0xF8 PUSH1 0x2 EXP SWAP1 DUP2 SWAP1 DIV DUP2 MUL DIV SWAP4 POP PUSH2 0x187 DUP6 PUSH1 0x1 PUSH2 0x25A JUMP JUMPDEST SWAP3 POP PUSH2 0x194 DUP6 PUSH1 0x15 PUSH2 0x2D6 JUMP JUMPDEST SWAP2 POP PUSH1 0x35 DUP6 MLOAD GT ISZERO PUSH2 0x1AE JUMPI PUSH2 0x1AB DUP6 PUSH1 0x35 PUSH2 0x2E9 JUMP JUMPDEST SWAP1 POP JUMPDEST SWAP2 SWAP4 POP SWAP2 SWAP4 JUMP JUMPDEST PUSH1 0x0 DUP1 DUP3 MLOAD PUSH1 0x15 EQ PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x22 DUP2 MSTORE PUSH1 0x20 ADD PUSH32 0x4D65746164617461206D75737420686176652061206C656E677468206F662032 DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xF1 PUSH1 0x2 EXP PUSH2 0x1897 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x225 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP DUP3 PUSH1 0x0 DUP2 MLOAD DUP2 LT ISZERO ISZERO PUSH2 0x235 JUMPI INVALID JUMPDEST ADD PUSH1 0x20 ADD MLOAD PUSH1 0xF8 PUSH1 0x2 EXP SWAP1 DUP2 SWAP1 DIV DUP2 MUL DIV SWAP2 POP PUSH2 0x253 DUP4 PUSH1 0x1 PUSH2 0x25A JUMP JUMPDEST SWAP1 POP SWAP2 POP SWAP2 JUMP JUMPDEST PUSH1 0x0 DUP2 PUSH1 0x14 ADD DUP4 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790191817 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x2C3 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP POP ADD PUSH1 0x14 ADD MLOAD PUSH1 0x1 PUSH1 0xA0 PUSH1 0x2 EXP SUB AND SWAP1 JUMP JUMPDEST PUSH1 0x0 PUSH2 0x2E2 DUP4 DUP4 PUSH2 0x426 JUMP JUMPDEST SWAP4 SWAP3 POP POP POP JUMP JUMPDEST PUSH1 0x60 PUSH1 0x0 DUP3 PUSH1 0x20 ADD DUP5 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790199917 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x354 JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP PUSH2 0x35F DUP5 DUP5 PUSH2 0x2D6 JUMP JUMPDEST SWAP1 POP DUP1 DUP4 PUSH1 0x20 ADD ADD DUP5 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790199917 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x3CA JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP DUP1 PUSH1 0x40 MLOAD SWAP1 DUP1 DUP3 MSTORE DUP1 PUSH1 0x1F ADD PUSH1 0x1F NOT AND PUSH1 0x20 ADD DUP3 ADD PUSH1 0x40 MSTORE DUP1 ISZERO PUSH2 0x3F9 JUMPI DUP2 PUSH1 0x20 ADD PUSH1 0x20 DUP3 MUL DUP1 CODESIZE DUP4 CODECOPY ADD SWAP1 POP JUMPDEST POP SWAP2 POP PUSH2 0x41F PUSH2 0x408 DUP4 PUSH2 0x499 JUMP JUMPDEST PUSH1 0x20 ADD DUP5 PUSH2 0x415 DUP8 PUSH2 0x499 JUMP JUMPDEST ADD PUSH1 0x20 ADD DUP4 PUSH2 0x49C JUMP JUMPDEST POP SWAP3 SWAP2 POP POP JUMP JUMPDEST PUSH1 0x0 DUP2 PUSH1 0x20 ADD DUP4 MLOAD LT ISZERO PUSH1 0x60 PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 PUSH1 0x2B DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0x0 DUP1 MLOAD PUSH1 0x20 PUSH2 0x738 DUP4 CODECOPY DUP2 MLOAD SWAP2 MSTORE DUP2 MSTORE PUSH1 0x20 ADD PUSH1 0xA9 PUSH1 0x2 EXP PUSH11 0x38BAB0B6103A3790199917 MUL DUP2 MSTORE POP SWAP1 ISZERO ISZERO PUSH2 0x48F JUMPI PUSH1 0x40 MLOAD PUSH1 0xE5 PUSH1 0x2 EXP PUSH3 0x461BCD MUL DUP2 MSTORE PUSH1 0x4 ADD PUSH2 0x150 SWAP2 SWAP1 PUSH2 0x61E JUMP JUMPDEST POP POP ADD PUSH1 0x20 ADD MLOAD SWAP1 JUMP JUMPDEST SWAP1 JUMP JUMPDEST DUP1 ISZERO ISZERO PUSH2 0x4A8 JUMPI PUSH2 0x533 JUMP JUMPDEST DUP3 DUP3 EQ ISZERO PUSH2 0x4B5 JUMPI PUSH2 0x533 JUMP JUMPDEST PUSH1 0x20 PUSH1 0x1F DUP3 ADD DIV PUSH1 0x20 DUP3 MOD PUSH1 0x0 DUP2 GT ISZERO PUSH2 0x4D0 JUMPI PUSH1 0x1 DUP3 SUB SWAP2 POP JUMPDEST PUSH1 0x0 PUSH1 0x20 DUP4 MUL JUMPDEST DUP1 DUP3 LT ISZERO PUSH2 0x4F2 JUMPI DUP2 DUP7 ADD MLOAD DUP3 DUP9 ADD MSTORE PUSH1 0x20 DUP3 ADD SWAP2 POP PUSH2 0x4D7 JUMP JUMPDEST PUSH1 0x0 DUP4 GT ISZERO PUSH2 0x52E JUMPI DUP3 PUSH1 0x20 SUB PUSH1 0x8 MUL PUSH1 0x2 EXP DUP3 DUP8 ADD MLOAD DUP2 DUP3 DUP3 DIV MUL DUP6 PUSH1 0x8 MUL PUSH1 0x2 EXP DUP6 DUP12 ADD MLOAD DUP2 DUP3 DUP3 MUL DIV DUP1 DUP5 OR DUP1 DUP10 DUP16 ADD MSTORE POP POP POP POP POP POP POP JUMPDEST POP POP POP POP JUMPDEST POP POP POP JUMP JUMPDEST PUSH1 0x0 PUSH1 0x1F DUP3 ADD DUP4 SGT PUSH2 0x549 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST DUP2 CALLDATALOAD PUSH2 0x55C PUSH2 0x557 DUP3 PUSH2 0x6B4 JUMP JUMPDEST PUSH2 0x68E JUMP JUMPDEST SWAP2 POP DUP1 DUP3 MSTORE PUSH1 0x20 DUP4 ADD PUSH1 0x20 DUP4 ADD DUP6 DUP4 DUP4 ADD GT ISZERO PUSH2 0x578 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH2 0x583 DUP4 DUP3 DUP5 PUSH2 0x6F1 JUMP JUMPDEST POP POP POP SWAP3 SWAP2 POP POP JUMP JUMPDEST PUSH1 0x0 PUSH1 0x20 DUP3 DUP5 SUB SLT ISZERO PUSH2 0x59E JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST DUP2 CALLDATALOAD PUSH1 0x1 PUSH1 0x40 PUSH1 0x2 EXP SUB DUP2 GT ISZERO PUSH2 0x5B4 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH2 0x5C0 DUP5 DUP3 DUP6 ADD PUSH2 0x538 JUMP JUMPDEST SWAP5 SWAP4 POP POP POP POP JUMP JUMPDEST PUSH2 0x5D1 DUP2 PUSH2 0x6DF JUMP JUMPDEST DUP3 MSTORE POP POP JUMP JUMPDEST PUSH1 0x0 PUSH2 0x5E2 DUP3 PUSH2 0x6DB JUMP JUMPDEST DUP1 DUP5 MSTORE PUSH2 0x5F6 DUP2 PUSH1 0x20 DUP7 ADD PUSH1 0x20 DUP7 ADD PUSH2 0x6FD JUMP JUMPDEST PUSH2 0x5FF DUP2 PUSH2 0x72D JUMP JUMPDEST SWAP1 SWAP4 ADD PUSH1 0x20 ADD SWAP4 SWAP3 POP POP POP JUMP JUMPDEST PUSH2 0x5D1 DUP2 PUSH2 0x499 JUMP JUMPDEST PUSH2 0x5D1 DUP2 PUSH2 0x6EB JUMP JUMPDEST PUSH1 0x20 DUP1 DUP3 MSTORE DUP2 ADD PUSH2 0x2E2 DUP2 DUP5 PUSH2 0x5D7 JUMP JUMPDEST PUSH1 0x40 DUP2 ADD PUSH2 0x63D DUP3 DUP6 PUSH2 0x615 JUMP JUMPDEST PUSH2 0x2E2 PUSH1 0x20 DUP4 ADD DUP5 PUSH2 0x5C8 JUMP JUMPDEST PUSH1 0x80 DUP2 ADD PUSH2 0x658 DUP3 DUP8 PUSH2 0x615 JUMP JUMPDEST PUSH2 0x665 PUSH1 0x20 DUP4 ADD DUP7 PUSH2 0x5C8 JUMP JUMPDEST PUSH2 0x672 PUSH1 0x40 DUP4 ADD DUP6 PUSH2 0x60C JUMP JUMPDEST DUP2 DUP2 SUB PUSH1 0x60 DUP4 ADD MSTORE PUSH2 0x684 DUP2 DUP5 PUSH2 0x5D7 JUMP JUMPDEST SWAP7 SWAP6 POP POP POP POP POP POP JUMP JUMPDEST PUSH1 0x40 MLOAD DUP2 DUP2 ADD PUSH1 0x1 PUSH1 0x40 PUSH1 0x2 EXP SUB DUP2 GT DUP3 DUP3 LT OR ISZERO PUSH2 0x6AC JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH1 0x40 MSTORE SWAP2 SWAP1 POP JUMP JUMPDEST PUSH1 0x0 PUSH1 0x1 PUSH1 0x40 PUSH1 0x2 EXP SUB DUP3 GT ISZERO PUSH2 0x6CA JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH1 0x20 PUSH1 0x1F SWAP2 SWAP1 SWAP2 ADD PUSH1 0x1F NOT AND ADD SWAP1 JUMP JUMPDEST MLOAD SWAP1 JUMP JUMPDEST PUSH1 0x1 PUSH1 0xA0 PUSH1 0x2 EXP SUB AND SWAP1 JUMP JUMPDEST PUSH1 0xFF AND SWAP1 JUMP JUMPDEST DUP3 DUP2 DUP4 CALLDATACOPY POP PUSH1 0x0 SWAP2 ADD MSTORE JUMP JUMPDEST PUSH1 0x0 JUMPDEST DUP4 DUP2 LT ISZERO PUSH2 0x718 JUMPI DUP2 DUP2 ADD MLOAD DUP4 DUP3 ADD MSTORE PUSH1 0x20 ADD PUSH2 0x700 JUMP JUMPDEST DUP4 DUP2 GT ISZERO PUSH2 0x727 JUMPI PUSH1 0x0 DUP5 DUP5 ADD MSTORE JUMPDEST POP POP POP POP JUMP JUMPDEST PUSH1 0x1F ADD PUSH1 0x1F NOT AND SWAP1 JUMP STOP 0x4c PUSH6 0x6E677468206D PUSH22 0x73742062652067726561746572207468616E206F7220 PUSH6 0xA265627A7A72 ADDRESS PC KECCAK256 MLOAD ORIGIN 0xeb PUSH21 0x48F5B6279DEDD3C042E96FB9EA0D8A8AEA79044353 PUSH4 0x8CF00546 AND 0x5f PUSH13 0x6578706572696D656E74616CF5 STOP CALLDATACOPY ",
+				"sourceMap": 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+			}
+		}
+	},
+	"sources": {
+		"current/test/TestLibAssetProxyDecoder/TestLibAssetProxyDecoder.sol": {
+			"id": 0
+		},
+		"current/utils/LibAssetProxyDecoder/LibAssetProxyDecoder.sol": {
+			"id": 1
+		},
+		"current/utils/LibBytes/LibBytes.sol": {
+			"id": 2
+		},
+		"current/utils/LibMem/LibMem.sol": {
+			"id": 3
+		}
+	},
+	"sourceCodes": {
+		"current/test/TestLibAssetProxyDecoder/TestLibAssetProxyDecoder.sol": "/*\n\n  Copyright 2018 ZeroEx Intl.\n\n  Licensed under the Apache License, Version 2.0 (the \"License\");\n  you may not use this file except in compliance with the License.\n  You may obtain a copy of the License at\n\n    http://www.apache.org/licenses/LICENSE-2.0\n\n  Unless required by applicable law or agreed to in writing, software\n  distributed under the License is distributed on an \"AS IS\" BASIS,\n  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n  See the License for the specific language governing permissions and\n  limitations under the License.\n\n*/\n\npragma solidity ^0.4.24;\npragma experimental ABIEncoderV2;\n\nimport \"../../utils/LibAssetProxyDecoder/LibAssetProxyDecoder.sol\";\n\ncontract TestLibAssetProxyDecoder is\n    LibAssetProxyDecoder\n{\n\n    /// @dev Decodes ERC721 Asset Proxy data\n    function publicDecodeERC20Data(bytes memory proxyData)\n        public\n        pure\n        returns (uint8, address)\n    {\n        return decodeERC20Data(proxyData);\n    }\n\n    /// @dev Decodes ERC721 Asset Proxy data\n    function publicDecodeERC721Data(bytes memory proxyData)\n        public\n        pure\n        returns (\n            uint8,\n            address,\n            uint256,\n            bytes memory\n        )\n    {\n        return decodeERC721Data(proxyData);\n    }\n}\n",
+		"current/utils/LibAssetProxyDecoder/LibAssetProxyDecoder.sol": "/*\n\n  Copyright 2018 ZeroEx Intl.\n\n  Licensed under the Apache License, Version 2.0 (the \"License\");\n  you may not use this file except in compliance with the License.\n  You may obtain a copy of the License at\n\n    http://www.apache.org/licenses/LICENSE-2.0\n\n  Unless required by applicable law or agreed to in writing, software\n  distributed under the License is distributed on an \"AS IS\" BASIS,\n  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n  See the License for the specific language governing permissions and\n  limitations under the License.\n\n*/\n\npragma solidity ^0.4.24;\npragma experimental ABIEncoderV2;\n\nimport \"../LibBytes/LibBytes.sol\";\n\ncontract LibAssetProxyDecoder is\n    LibBytes\n{\n\n    string constant INVALID_ERC20_METADATA_LENGTH = \"Metadata must have a length of 21.\";\n    string constant INVALID_ERC721_METADATA_LENGTH = \"Metadata must have a length of at least 53.\";\n\n    /// @dev Decodes ERC721 Asset Proxy data\n    function decodeERC20Data(bytes memory proxyData)\n        internal\n        pure\n        returns (\n            uint8 proxyId,\n            address token\n        )\n    {\n        require(\n            proxyData.length == 21,\n            INVALID_ERC20_METADATA_LENGTH\n        );\n        proxyId = uint8(proxyData[0]);\n        token = readAddress(proxyData, 1);\n\n        return (proxyId, token);\n    }\n\n    /// @dev Decodes ERC721 Asset Proxy data\n    function decodeERC721Data(bytes memory proxyData)\n        internal\n        pure\n        returns (\n            uint8 proxyId,\n            address token,\n            uint256 tokenId,\n            bytes memory data\n        )\n    {\n        require(\n            proxyData.length >= 53,\n            INVALID_ERC721_METADATA_LENGTH\n        );\n        proxyId = uint8(proxyData[0]);\n        token = readAddress(proxyData, 1);\n        tokenId = readUint256(proxyData, 21);\n        if (proxyData.length > 53) {\n            data = readBytes(proxyData, 53);\n        }\n\n        return (proxyId, token, tokenId, data);\n    }\n}\n",
+		"current/utils/LibBytes/LibBytes.sol": "/*\n\n  Copyright 2018 ZeroEx Intl.\n\n  Licensed under the Apache License, Version 2.0 (the \"License\");\n  you may not use this file except in compliance with the License.\n  You may obtain a copy of the License at\n\n    http://www.apache.org/licenses/LICENSE-2.0\n\n  Unless required by applicable law or agreed to in writing, software\n  distributed under the License is distributed on an \"AS IS\" BASIS,\n  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n  See the License for the specific language governing permissions and\n  limitations under the License.\n\n*/\n\npragma solidity ^0.4.24;\n\nimport \"../LibMem/LibMem.sol\";\n\ncontract LibBytes is\n    LibMem\n{\n\n    // Revert reasons\n    string constant GTE_20_LENGTH_REQUIRED = \"Length must be greater than or equal to 20.\";\n    string constant GTE_32_LENGTH_REQUIRED = \"Length must be greater than or equal to 32.\";\n\n    /// @dev Tests equality of two byte arrays.\n    /// @param lhs First byte array to compare.\n    /// @param rhs Second byte array to compare.\n    /// @return True if arrays are the same. False otherwise.\n    function areBytesEqual(bytes memory lhs, bytes memory rhs)\n        internal\n        pure\n        returns (bool equal)\n    {\n        assembly {\n            // Get the number of words occupied by <lhs>\n            let lenFullWords := div(add(mload(lhs), 0x1F), 0x20)\n\n            // Add 1 to the number of words, to account for the length field\n            lenFullWords := add(lenFullWords, 0x1)\n\n            // Test equality word-by-word.\n            // Terminates early if there is a mismatch.\n            for {let i := 0} lt(i, lenFullWords) {i := add(i, 1)} {\n                let lhsWord := mload(add(lhs, mul(i, 0x20)))\n                let rhsWord := mload(add(rhs, mul(i, 0x20)))\n                equal := eq(lhsWord, rhsWord)\n                if eq(equal, 0) {\n                    // Break\n                    i := lenFullWords\n                }\n            }\n       }\n\n       return equal;\n    }\n\n    /// @dev Reads an address from a position in a byte array.\n    /// @param b Byte array containing an address.\n    /// @param index Index in byte array of address.\n    /// @return address from byte array.\n    function readAddress(\n        bytes memory b,\n        uint256 index\n    )\n        internal\n        pure\n        returns (address result)\n    {\n        require(\n            b.length >= index + 20,  // 20 is length of address\n            GTE_20_LENGTH_REQUIRED\n        );\n\n        // Add offset to index:\n        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)\n        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)\n        index += 20;\n\n        // Read address from array memory\n        assembly {\n            // 1. Add index to address of bytes array\n            // 2. Load 32-byte word from memory\n            // 3. Apply 20-byte mask to obtain address\n            result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)\n        }\n        return result;\n    }\n\n    /// @dev Writes an address into a specific position in a byte array.\n    /// @param b Byte array to insert address into.\n    /// @param index Index in byte array of address.\n    /// @param input Address to put into byte array.\n    function writeAddress(\n        bytes memory b,\n        uint256 index,\n        address input\n    )\n        internal\n        pure\n    {\n        require(\n            b.length >= index + 20,  // 20 is length of address\n            GTE_20_LENGTH_REQUIRED\n        );\n\n        // Add offset to index:\n        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)\n        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)\n        index += 20;\n\n        // Store address into array memory\n        assembly {\n            // The address occupies 20 bytes and mstore stores 32 bytes.\n            // First fetch the 32-byte word where we'll be storing the address, then\n            // apply a mask so we have only the bytes in the word that the address will not occupy.\n            // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.\n\n            // 1. Add index to address of bytes array\n            // 2. Load 32-byte word from memory\n            // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address\n            let neighbors := and(mload(add(b, index)), 0xffffffffffffffffffffffff0000000000000000000000000000000000000000)\n\n            // Store the neighbors and address into memory\n            mstore(add(b, index), xor(input, neighbors))\n        }\n    }\n\n    /// @dev Reads a bytes32 value from a position in a byte array.\n    /// @param b Byte array containing a bytes32 value.\n    /// @param index Index in byte array of bytes32 value.\n    /// @return bytes32 value from byte array.\n    function readBytes32(\n        bytes memory b,\n        uint256 index\n    )\n        internal\n        pure\n        returns (bytes32 result)\n    {\n        require(\n            b.length >= index + 32,\n            GTE_32_LENGTH_REQUIRED\n        );\n\n        // Arrays are prefixed by a 256 bit length parameter\n        index += 32;\n\n        // Read the bytes32 from array memory\n        assembly {\n            result := mload(add(b, index))\n        }\n        return result;\n    }\n\n    /// @dev Writes a bytes32 into a specific position in a byte array.\n    /// @param b Byte array to insert <input> into.\n    /// @param index Index in byte array of <input>.\n    /// @param input bytes32 to put into byte array.\n    function writeBytes32(\n        bytes memory b,\n        uint256 index,\n        bytes32 input\n    )\n        internal\n        pure\n    {\n        require(\n            b.length >= index + 32,\n            GTE_32_LENGTH_REQUIRED\n        );\n\n        // Arrays are prefixed by a 256 bit length parameter\n        index += 32;\n\n        // Read the bytes32 from array memory\n        assembly {\n            mstore(add(b, index), input)\n        }\n    }\n\n    /// @dev Reads a uint256 value from a position in a byte array.\n    /// @param b Byte array containing a uint256 value.\n    /// @param index Index in byte array of uint256 value.\n    /// @return uint256 value from byte array.\n    function readUint256(\n        bytes memory b,\n        uint256 index\n    )\n        internal\n        pure\n        returns (uint256 result)\n    {\n        return uint256(readBytes32(b, index));\n    }\n\n    /// @dev Writes a uint256 into a specific position in a byte array.\n    /// @param b Byte array to insert <input> into.\n    /// @param index Index in byte array of <input>.\n    /// @param input uint256 to put into byte array.\n    function writeUint256(\n        bytes memory b,\n        uint256 index,\n        uint256 input\n    )\n        internal\n        pure\n    {\n        writeBytes32(b, index, bytes32(input));\n    }\n\n    /// @dev Reads a uint256 value from a position in a byte array.\n    /// @param b Byte array containing a uint256 value.\n    /// @param index Index in byte array of uint256 value.\n    /// @return uint256 value from byte array.\n    function readBytes(\n        bytes memory b,\n        uint256 index\n    )\n        internal\n        pure\n        returns (bytes memory result)\n    {\n        // Read length of nested bytes\n        require(\n            b.length >= index + 32,\n            GTE_32_LENGTH_REQUIRED\n        );\n        uint256 nestedBytesLength = readUint256(b, index);\n\n        // Assert length of <b> is valid, given\n        // length of nested bytes\n        require(\n            b.length >= index + 32 + nestedBytesLength,\n            GTE_32_LENGTH_REQUIRED\n        );\n\n        // Allocate memory and copy value to result\n        result = new bytes(nestedBytesLength);\n        memcpy(\n            getMemAddress(result) + 32,    // +32 skips array length\n            getMemAddress(b) + index + 32, // +32 skips array length\n            nestedBytesLength\n        );\n\n        return result;\n    }\n\n    /// @dev Writes a uint256 into a specific position in a byte array.\n    /// @param b Byte array to insert <input> into.\n    /// @param index Index in byte array of <input>.\n    /// @param input uint256 to put into byte array.\n    function writeBytes(\n        bytes memory b,\n        uint256 index,\n        bytes memory input\n    )\n        internal\n        pure\n    {\n        // Read length of nested bytes\n        require(\n            b.length >= index + 32 /* 32 bytes to store length */ + input.length,\n            GTE_32_LENGTH_REQUIRED\n        );\n\n        // Copy <input> into <b>\n        memcpy(\n            getMemAddress(b) + index,\n            getMemAddress(input),\n            input.length + 32 /* 32 bytes to store length */\n        );\n    }\n}\n",
+		"current/utils/LibMem/LibMem.sol": "/*\n\n  Copyright 2018 ZeroEx Intl.\n\n  Licensed under the Apache License, Version 2.0 (the \"License\");\n  you may not use this file except in compliance with the License.\n  You may obtain a copy of the License at\n\n    http://www.apache.org/licenses/LICENSE-2.0\n\n  Unless required by applicable law or agreed to in writing, software\n  distributed under the License is distributed on an \"AS IS\" BASIS,\n  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n  See the License for the specific language governing permissions and\n  limitations under the License.\n\n*/\n\npragma solidity ^0.4.24;\n\ncontract LibMem {\n\n    function getMemAddress(bytes memory input)\n        internal\n        pure\n        returns (uint256 address_)\n    {\n        assembly {\n            address_ := input\n        }\n        return address_;\n    }\n\n    /// @dev Writes a uint256 into a specific position in a byte array.\n    /// @param dest memory adress to copy bytes to\n    function memcpy(\n        uint256 dest,\n        uint256 source,\n        uint256 length\n    )\n        internal\n        pure\n    {\n        // Base cases\n        if(length == 0) return;\n        if(source == dest) return;\n\n        // Copy bytes from source to dest\n        assembly {\n            // Compute number of complete words to copy + remaining bytes\n            let lenFullWords := div(add(length, 0x1F), 0x20)\n            let remainder := mod(length, 0x20)\n            if gt(remainder, 0) {\n                lenFullWords := sub(lenFullWords, 1)\n            }\n\n            // Copy full words from source to dest\n            let offset := 0\n            let maxOffset := mul(0x20, lenFullWords)\n            for {offset := 0} lt(offset, maxOffset) {offset := add(offset, 0x20)} {\n                mstore(add(dest, offset),  mload(add(source, offset)))\n            }\n\n            // Copy remaining bytes\n            if gt(remainder, 0) {\n                // Read a full word from source, containing X bytes to copy to dest.\n                // We only want to keep the X bytes, zeroing out the remaining bytes.\n                // We accomplish this by a right shift followed by a left shift.\n                // Example:\n                //   Suppose a word of 8 bits has all 1's: [11111111]\n                //   Let X = 7 (we want to copy the first 7 bits)\n                //   Apply a right shift of 1: [01111111]\n                //   Apply a left shift of 1: [11111110]\n                let sourceShiftFactor := exp(2, mul(8, sub(0x20, remainder)))\n                let sourceWord := mload(add(source, offset))\n                let sourceBytes := mul(div(sourceWord, sourceShiftFactor), sourceShiftFactor)\n\n                // Read a full word from dest, containing (32-X) bytes to retain.\n                // We need to zero out the remaining bytes to be overwritten by source,\n                // while retaining the (32-X) bytes we don't want to overwrite.\n                // We accomplish this by a left shift followed by a right shift.\n                // Example:\n                //   Suppose a word of 8 bits has all 1's: [11111111]\n                //   Let X = 7 (we want to free the first 7 bits, and retain the last bit)\n                //   Apply a left shift of 1: [11111110]\n                //   Apply a right shift of 1: [01111111]\n                let destShiftFactor := exp(2, mul(8, remainder))\n                let destWord := mload(add(dest, offset))\n                let destBytes := div(mul(destWord, destShiftFactor), destShiftFactor)\n\n                // Combine the source and dest bytes. There should be no overlap:\n                // The source bytes run from [0..X-1] and the dest bytes from [X..31].\n                // Example:\n                //   Following the example from above, we have [11111110]\n                //   from the source word and [01111111] from the dest word.\n                //   Combine these words using <or> to get [11111111].\n                let combinedDestWord := or(sourceBytes, destBytes)\n\n                // Store the combined word into dest\n                mstore(add(dest, offset), combinedDestWord)\n            }\n        }\n    }\n}\n"
+	},
+	"sourceTreeHashHex": "0x872ca57a3559c6ce5cd050e72e3b25fdfc98cb222b1835d097ee16dc444c1733",
+	"compiler": {
+		"name": "solc",
+		"version": "0.4.24",
+		"settings": {
+			"optimizer": {
+				"enabled": true,
+				"runs": 0
+			},
+			"outputSelection": {
+				"*": {
+					"*": [
+						"abi",
+						"evm.bytecode.object",
+						"evm.bytecode.sourceMap",
+						"evm.deployedBytecode.object",
+						"evm.deployedBytecode.sourceMap"
+					]
+				}
+			}
+		}
+	},
+	"networks": {}
+}
\ No newline at end of file
diff --git a/packages/order-utils/src/asset_proxy_utils.ts b/packages/order-utils/src/asset_proxy_utils.ts
index 55f2d56df..915ee5032 100644
--- a/packages/order-utils/src/asset_proxy_utils.ts
+++ b/packages/order-utils/src/asset_proxy_utils.ts
@@ -1,10 +1,15 @@
-import { AssetProxyId, ERC20ProxyData, ERC721ProxyData, ProxyData } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
+import { AssetProxyId, ERC20AssetData, ERC721AssetData } from '@0xproject/types';
+import { BigNumber, NULL_BYTES } from '@0xproject/utils';
 import BN = require('bn.js');
 import ethUtil = require('ethereumjs-util');
+import * as _ from 'lodash';
 
-const ERC20_PROXY_METADATA_BYTE_LENGTH = 21;
-const ERC721_PROXY_METADATA_BYTE_LENGTH = 53;
+const ERC20_ASSET_DATA_BYTE_LENGTH = 21;
+const ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH = 53;
+const ASSET_DATA_ADDRESS_OFFSET = 0;
+const ERC721_ASSET_DATA_TOKEN_ID_OFFSET = 20;
+const ERC721_ASSET_DATA_RECEIVER_DATA_LENGTH_OFFSET = 52;
+const ERC721_ASSET_DATA_RECEIVER_DATA_OFFSET = 84;
 
 export const assetProxyUtils = {
     encodeAssetProxyId(assetProxyId: AssetProxyId): Buffer {
@@ -40,23 +45,24 @@ export const assetProxyUtils = {
         const value = new BigNumber(formattedValue, 16);
         return value;
     },
-    encodeERC20ProxyData(tokenAddress: string): string {
+    encodeERC20AssetData(tokenAddress: string): string {
         const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC20);
         const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress);
-        const encodedMetadata = Buffer.concat([encodedAddress, encodedAssetProxyId]);
-        const encodedMetadataHex = ethUtil.bufferToHex(encodedMetadata);
-        return encodedMetadataHex;
+        const encodedAssetData = Buffer.concat([encodedAddress, encodedAssetProxyId]);
+        const encodedAssetDataHex = ethUtil.bufferToHex(encodedAssetData);
+        return encodedAssetDataHex;
     },
-    decodeERC20ProxyData(proxyData: string): ERC20ProxyData {
-        const encodedProxyMetadata = ethUtil.toBuffer(proxyData);
-        if (encodedProxyMetadata.byteLength !== ERC20_PROXY_METADATA_BYTE_LENGTH) {
+    decodeERC20AssetData(proxyData: string): ERC20AssetData {
+        const encodedAssetData = ethUtil.toBuffer(proxyData);
+        if (encodedAssetData.byteLength !== ERC20_ASSET_DATA_BYTE_LENGTH) {
             throw new Error(
                 `Could not decode ERC20 Proxy Data. Expected length of encoded data to be 21. Got ${
-                    encodedProxyMetadata.byteLength
+                    encodedAssetData.byteLength
                 }`,
             );
         }
-        const encodedAssetProxyId = encodedProxyMetadata.slice(-1);
+        const assetProxyIdOffset = encodedAssetData.byteLength - 1;
+        const encodedAssetProxyId = encodedAssetData.slice(assetProxyIdOffset);
         const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
         if (assetProxyId !== AssetProxyId.ERC20) {
             throw new Error(
@@ -65,33 +71,45 @@ export const assetProxyUtils = {
                 }), but got ${assetProxyId}`,
             );
         }
-        const addressOffset = ERC20_PROXY_METADATA_BYTE_LENGTH - 1;
-        const encodedTokenAddress = encodedProxyMetadata.slice(0, addressOffset);
+        const encodedTokenAddress = encodedAssetData.slice(ASSET_DATA_ADDRESS_OFFSET, assetProxyIdOffset);
         const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
-        const erc20ProxyData = {
+        const erc20AssetData = {
             assetProxyId,
             tokenAddress,
         };
-        return erc20ProxyData;
+        return erc20AssetData;
     },
-    encodeERC721ProxyData(tokenAddress: string, tokenId: BigNumber): string {
+    encodeERC721AssetData(tokenAddress: string, tokenId: BigNumber, receiverData?: string): string {
         const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC721);
         const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress);
         const encodedTokenId = assetProxyUtils.encodeUint256(tokenId);
-        const encodedMetadata = Buffer.concat([encodedAddress, encodedTokenId, encodedAssetProxyId]);
-        const encodedMetadataHex = ethUtil.bufferToHex(encodedMetadata);
-        return encodedMetadataHex;
+        let encodedAssetData = Buffer.concat([encodedAddress, encodedTokenId]);
+        if (!_.isUndefined(receiverData)) {
+            const encodedReceiverData = ethUtil.toBuffer(receiverData);
+            const receiverDataLength = new BigNumber(encodedReceiverData.byteLength);
+            const encodedReceiverDataLength = assetProxyUtils.encodeUint256(receiverDataLength);
+            encodedAssetData = Buffer.concat([encodedAssetData, encodedReceiverDataLength, encodedReceiverData]);
+        }
+        encodedAssetData = Buffer.concat([encodedAssetData, encodedAssetProxyId]);
+        const encodedAssetDataHex = ethUtil.bufferToHex(encodedAssetData);
+        return encodedAssetDataHex;
     },
-    decodeERC721ProxyData(proxyData: string): ERC721ProxyData {
-        const encodedProxyMetadata = ethUtil.toBuffer(proxyData);
-        if (encodedProxyMetadata.byteLength !== ERC721_PROXY_METADATA_BYTE_LENGTH) {
+    decodeERC721AssetData(assetData: string): ERC721AssetData {
+        const encodedAssetData = ethUtil.toBuffer(assetData);
+        if (encodedAssetData.byteLength < ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH) {
             throw new Error(
-                `Could not decode ERC20 Proxy Data. Expected length of encoded data to be 53. Got ${
-                    encodedProxyMetadata.byteLength
+                `Could not decode ERC20 Proxy Data. Expected length of encoded data to be at least 53. Got ${
+                    encodedAssetData.byteLength
                 }`,
             );
         }
-        const encodedAssetProxyId = encodedProxyMetadata.slice(-1);
+
+        const encodedTokenAddress = encodedAssetData.slice(
+            ASSET_DATA_ADDRESS_OFFSET,
+            ERC721_ASSET_DATA_TOKEN_ID_OFFSET,
+        );
+        const proxyIdOffset = encodedAssetData.byteLength - 1;
+        const encodedAssetProxyId = encodedAssetData.slice(proxyIdOffset);
         const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
         if (assetProxyId !== AssetProxyId.ERC721) {
             throw new Error(
@@ -100,50 +118,63 @@ export const assetProxyUtils = {
                 }), but got ${assetProxyId}`,
             );
         }
-        const addressOffset = ERC20_PROXY_METADATA_BYTE_LENGTH - 1;
-        const encodedTokenAddress = encodedProxyMetadata.slice(0, addressOffset);
         const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
-        const tokenIdOffset = ERC721_PROXY_METADATA_BYTE_LENGTH - 1;
-        const encodedTokenId = encodedProxyMetadata.slice(addressOffset, tokenIdOffset);
+        const encodedTokenId = encodedAssetData.slice(
+            ERC721_ASSET_DATA_TOKEN_ID_OFFSET,
+            ERC721_ASSET_DATA_RECEIVER_DATA_LENGTH_OFFSET,
+        );
         const tokenId = assetProxyUtils.decodeUint256(encodedTokenId);
-        const erc721ProxyData = {
+        let receiverData = NULL_BYTES;
+        const lengthUpToReceiverDataLength = ERC721_ASSET_DATA_RECEIVER_DATA_LENGTH_OFFSET + 1;
+        if (encodedAssetData.byteLength > lengthUpToReceiverDataLength) {
+            const encodedReceiverDataLength = encodedAssetData.slice(
+                ERC721_ASSET_DATA_RECEIVER_DATA_LENGTH_OFFSET,
+                ERC721_ASSET_DATA_RECEIVER_DATA_OFFSET,
+            );
+            const receiverDataLength = assetProxyUtils.decodeUint256(encodedReceiverDataLength);
+            const lengthUpToReceiverData = ERC721_ASSET_DATA_RECEIVER_DATA_OFFSET + 1;
+            const expectedReceiverDataLength = new BigNumber(encodedAssetData.byteLength - lengthUpToReceiverData);
+            if (!receiverDataLength.equals(expectedReceiverDataLength)) {
+                throw new Error(
+                    `Data length (${receiverDataLength}) does not match actual length of data (${expectedReceiverDataLength})`,
+                );
+            }
+            const encodedReceiverData = encodedAssetData.slice(
+                ERC721_ASSET_DATA_RECEIVER_DATA_OFFSET,
+                receiverDataLength.add(ERC721_ASSET_DATA_RECEIVER_DATA_OFFSET).toNumber(),
+            );
+            receiverData = ethUtil.bufferToHex(encodedReceiverData);
+        }
+        const erc721AssetData: ERC721AssetData = {
             assetProxyId,
             tokenAddress,
             tokenId,
+            receiverData,
         };
-        return erc721ProxyData;
+        return erc721AssetData;
     },
-    decodeProxyDataId(proxyData: string): AssetProxyId {
-        const encodedProxyMetadata = ethUtil.toBuffer(proxyData);
-        if (encodedProxyMetadata.byteLength < 1) {
+    decodeAssetDataId(assetData: string): AssetProxyId {
+        const encodedAssetData = ethUtil.toBuffer(assetData);
+        if (encodedAssetData.byteLength < 1) {
             throw new Error(
                 `Could not decode Proxy Data. Expected length of encoded data to be at least 1. Got ${
-                    encodedProxyMetadata.byteLength
+                    encodedAssetData.byteLength
                 }`,
             );
         }
-        const encodedAssetProxyId = encodedProxyMetadata.slice(-1);
+        const encodedAssetProxyId = encodedAssetData.slice(-1);
         const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
         return assetProxyId;
     },
-    decodeProxyData(proxyData: string): ProxyData {
-        const assetProxyId = assetProxyUtils.decodeProxyDataId(proxyData);
+    decodeAssetData(assetData: string): ERC20AssetData | ERC721AssetData {
+        const assetProxyId = assetProxyUtils.decodeAssetDataId(assetData);
         switch (assetProxyId) {
             case AssetProxyId.ERC20:
-                const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(proxyData);
-                const generalizedERC20ProxyData = {
-                    assetProxyId,
-                    tokenAddress: erc20ProxyData.tokenAddress,
-                };
-                return generalizedERC20ProxyData;
+                const erc20AssetData = assetProxyUtils.decodeERC20AssetData(assetData);
+                return erc20AssetData;
             case AssetProxyId.ERC721:
-                const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(proxyData);
-                const generaliedERC721ProxyData = {
-                    assetProxyId,
-                    tokenAddress: erc721ProxyData.tokenAddress,
-                    data: erc721ProxyData.tokenId,
-                };
-                return generaliedERC721ProxyData;
+                const erc721AssetData = assetProxyUtils.decodeERC721AssetData(assetData);
+                return erc721AssetData;
             default:
                 throw new Error(`Unrecognized asset proxy id: ${assetProxyId}`);
         }
diff --git a/packages/order-utils/src/order_state_utils.ts b/packages/order-utils/src/order_state_utils.ts
index ca18097c9..40f235da7 100644
--- a/packages/order-utils/src/order_state_utils.ts
+++ b/packages/order-utils/src/order_state_utils.ts
@@ -79,7 +79,7 @@ export class OrderStateUtils {
     }
     public async getOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
         const zrxTokenAddress = this._orderFilledCancelledFetcher.getZRXTokenAddress();
-        const makerProxyData = assetProxyUtils.decodeERC20ProxyData(signedOrder.makerAssetData);
+        const makerProxyData = assetProxyUtils.decodeERC20AssetData(signedOrder.makerAssetData);
         const makerAssetAddress = makerProxyData.tokenAddress;
         const orderHash = orderHashUtils.getOrderHashHex(signedOrder);
         const makerBalance = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(
@@ -111,7 +111,7 @@ export class OrderStateUtils {
         const transferrableMakerAssetAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
         const transferrableFeeAssetAmount = BigNumber.min([makerFeeProxyAllowance, makerFeeBalance]);
 
-        const zrxAssetData = assetProxyUtils.encodeERC20ProxyData(zrxTokenAddress);
+        const zrxAssetData = assetProxyUtils.encodeERC20AssetData(zrxTokenAddress);
         const isMakerAssetZRX = signedOrder.makerAssetData === zrxAssetData;
         const remainingFillableCalculator = new RemainingFillableCalculator(
             signedOrder.makerFee,
diff --git a/packages/types/src/index.ts b/packages/types/src/index.ts
index 5ba66158e..a5da947e1 100644
--- a/packages/types/src/index.ts
+++ b/packages/types/src/index.ts
@@ -156,19 +156,14 @@ export enum AssetProxyId {
     ERC721,
 }
 
-export interface ERC20ProxyData {
+export interface ERC20AssetData {
     assetProxyId: AssetProxyId;
     tokenAddress: string;
 }
 
-export interface ERC721ProxyData {
+export interface ERC721AssetData {
     assetProxyId: AssetProxyId;
     tokenAddress: string;
     tokenId: BigNumber;
-}
-
-export interface ProxyData {
-    assetProxyId: AssetProxyId;
-    tokenAddress?: string;
-    data?: any;
+    receiverData: string;
 }