Merge development

28 files changed, 3478 insertions, 0 deletions

diff --git a/contracts/asset-proxy/CHANGELOG.json b/contracts/asset-proxy/CHANGELOG.json
new file mode 100644
index 000000000..9307f7da4
--- /dev/null
+++ b/contracts/asset-proxy/CHANGELOG.json
@@ -0,0 +1,11 @@
+[
+    {
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "Move all AssetProxy contracts out of contracts-protocol to new package",
+                "pr": 1539
+            }
+        ]
+    }
+]
diff --git a/contracts/asset-proxy/CHANGELOG.md b/contracts/asset-proxy/CHANGELOG.md
new file mode 100644
index 000000000..779eb68a7
--- /dev/null
+++ b/contracts/asset-proxy/CHANGELOG.md
@@ -0,0 +1,28 @@
+<!--
+changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
+Edit the package's CHANGELOG.json file only.
+-->
+
+CHANGELOG
+
+## v2.2.3 - _January 17, 2019_
+
+    * Dependencies updated
+
+## v2.2.2 - _January 15, 2019_
+
+    * Dependencies updated
+
+## v2.2.1 - _January 11, 2019_
+
+    * Dependencies updated
+
+## v2.2.0 - _January 9, 2019_
+
+    * Added LibAddressArray (#1383)
+    * Add validation and comments to MultiAssetProxy (#1455)
+    * Move OrderValidator to extensions (#1464)
+
+## v2.1.59 - _December 13, 2018_
+
+    * Dependencies updated
diff --git a/contracts/asset-proxy/DEPLOYS.json b/contracts/asset-proxy/DEPLOYS.json
new file mode 100644
index 000000000..0f25da1c3
--- /dev/null
+++ b/contracts/asset-proxy/DEPLOYS.json
@@ -0,0 +1,47 @@
+[
+    {
+        "name": "MultiAssetProxy",
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "Add MultiAssetProxy implementation",
+                "pr": 1224,
+                "networks": {
+                    "3": "0xab8fbd189c569ccdee3a4d929bb7f557be4028f6",
+                    "4": "0xb34cde0ad3a83d04abebc0b66e75196f22216621",
+                    "42": "0xf6313a772c222f51c28f2304c0703b8cf5428fd8"
+                }
+            }
+        ]
+    },
+    {
+        "name": "ERC20Proxy",
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "protocol v2 deploy",
+                "networks": {
+                    "1": "0x2240dab907db71e64d3e0dba4800c83b5c502d4e",
+                    "3": "0xb1408f4c245a23c31b98d2c626777d4c0d766caa",
+                    "4": "0x3e809c563c15a295e832e37053798ddc8d6c8dab",
+                    "42": "0xf1ec01d6236d3cd881a0bf0130ea25fe4234003e"
+                }
+            }
+        ]
+    },
+    {
+        "name": "ERC721Proxy",
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "protocol v2 deploy",
+                "networks": {
+                    "1": "0x208e41fb445f1bb1b6780d58356e81405f3e6127",
+                    "3": "0xe654aac058bfbf9f83fcaee7793311dd82f6ddb4",
+                    "4": "0x8e1ff02637cb5e39f2fa36c14706aa348b065b09",
+                    "42": "0x2a9127c745688a165106c11cd4d647d2220af821"
+                }
+            }
+        ]
+    }
+]
diff --git a/contracts/asset-proxy/README.md b/contracts/asset-proxy/README.md
new file mode 100644
index 000000000..48a5b20a5
--- /dev/null
+++ b/contracts/asset-proxy/README.md
@@ -0,0 +1,73 @@
+## AssetProxy
+
+This package contains the implementations of all of the [`AssetProxy`](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#assetproxy) contracts available within the 0x protocol. These contracts are responsible for decoding the `assetData` sent to them and performing the actual transfer of assets. Addresses of the deployed contracts can be found in the 0x [wiki](https://0xproject.com/wiki#Deployed-Addresses) or the [DEPLOYS](./DEPLOYS.json) file within this package.
+
+## Installation
+
+**Install**
+
+```bash
+npm install @0x/contracts-asset-proxy --save
+```
+
+## Bug bounty
+
+A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0xproject.com/wiki#Bug-Bounty).
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
+
+Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+
+```bash
+yarn install
+```
+
+### Build
+
+To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
+
+```bash
+PKG=@0x/contracts-asset-proxy yarn build
+```
+
+Or continuously rebuild on change:
+
+```bash
+PKG=@0x/contracts-asset-proxy yarn watch
+```
+
+### Clean
+
+```bash
+yarn clean
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
+```
+
+#### Testing options
+
+Contracts testing options like coverage, profiling, revert traces or backing node choosing - are described [here](../TESTING.md).
diff --git a/contracts/asset-proxy/compiler.json b/contracts/asset-proxy/compiler.json
new file mode 100644
index 000000000..70d4c6b20
--- /dev/null
+++ b/contracts/asset-proxy/compiler.json
@@ -0,0 +1,31 @@
+{
+    "artifactsDir": "./generated-artifacts",
+    "contractsDir": "./contracts",
+    "useDockerisedSolc": true,
+    "compilerSettings": {
+        "optimizer": {
+            "enabled": true,
+            "runs": 1000000
+        },
+        "outputSelection": {
+            "*": {
+                "*": [
+                    "abi",
+                    "evm.bytecode.object",
+                    "evm.bytecode.sourceMap",
+                    "evm.deployedBytecode.object",
+                    "evm.deployedBytecode.sourceMap"
+                ]
+            }
+        }
+    },
+    "contracts": [
+        "IAssetData",
+        "IAssetProxy",
+        "IAuthorizable",
+        "ERC20Proxy",
+        "ERC721Proxy",
+        "MixinAuthorizable",
+        "MultiAssetProxy"
+    ]
+}
diff --git a/contracts/asset-proxy/contracts/src/ERC20Proxy.sol b/contracts/asset-proxy/contracts/src/ERC20Proxy.sol
new file mode 100644
index 000000000..258443bca
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/ERC20Proxy.sol
@@ -0,0 +1,184 @@
+/*
+
+  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 "./MixinAuthorizable.sol";
+
+
+contract ERC20Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant internal PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
+    
+    // solhint-disable-next-line payable-fallback
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                // `transferFrom`.
+                // The function is marked `external`, so no abi decodeding is done for
+                // us. Instead, we expect the `calldata` memory to contain the
+                // following:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. offset to assetData (*)        |
+                // |          | 36     |         |   2. from                           |
+                // |          | 68     |         |   3. to                             |
+                // |          | 100    |         |   4. amount                         |
+                // | Data     |        |         | assetData:                          |
+                // |          | 132    | 32      | assetData Length                    |
+                // |          | 164    | **      | assetData Contents                  |
+                //
+                // (*): offset is computed from start of function parameters, so offset
+                //      by an additional 4 bytes in the calldata.
+                //
+                // (**): see table below to compute length of assetData Contents
+                //
+                // WARNING: The ABIv2 specification allows additional padding between
+                //          the Params and Data section. This will result in a larger
+                //          offset to assetData.
+
+                // Asset data itself is encoded as follows:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 1 * 32  | function parameters:                |
+                // |          | 4      | 12 + 20 |   1. token address                  |
+
+                // We construct calldata for the `token.transferFrom` ABI.
+                // The layout of this calldata is in the table below.
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 3 * 32  | function parameters:                |
+                // |          | 4      |         |   1. from                           |
+                // |          | 36     |         |   2. to                             |
+                // |          | 68     |         |   3. amount                         |
+
+                /////// Read token address from calldata ///////
+                // * The token address is stored in `assetData`.
+                //
+                // * The "offset to assetData" is stored at offset 4 in the calldata (table 1).
+                //   [assetDataOffsetFromParams = calldataload(4)]
+                //
+                // * Notes that the "offset to assetData" is relative to the "Params" area of calldata;
+                //   add 4 bytes to account for the length of the "Header" area (table 1).
+                //   [assetDataOffsetFromHeader = assetDataOffsetFromParams + 4]
+                //
+                // * The "token address" is offset 32+4=36 bytes into "assetData" (tables 1 & 2).
+                //   [tokenOffset = assetDataOffsetFromHeader + 36 = calldataload(4) + 4 + 36]
+                let token := calldataload(add(calldataload(4), 40))
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFrom` selector.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(0, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // We copy the fields `from`, `to` and `amount` in bulk
+                // from our own calldata to the new calldata.
+                calldatacopy(4, 36, 96)
+
+                /////// Call `token.transferFrom` using the calldata ///////
+                let success := call(
+                    gas,            // forward all gas
+                    token,          // call address of token contract
+                    0,              // don't send any ETH
+                    0,              // pointer to start of input
+                    100,            // length of input
+                    0,              // write output over input
+                    32              // output size should be 32 bytes
+                )
+
+                /////// Check return data. ///////
+                // If there is no return data, we assume the token incorrectly
+                // does not return a bool. In this case we expect it to revert
+                // on failure, which was handled above.
+                // If the token does return data, we require that it is a single
+                // nonzero 32 bytes value.
+                // So the transfer succeeded if the call succeeded and either
+                // returned nothing, or returned a non-zero 32 byte value. 
+                success := and(success, or(
+                    iszero(returndatasize),
+                    and(
+                        eq(returndatasize, 32),
+                        gt(mload(0), 0)
+                    )
+                ))
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+
+            // Revert if undefined function is called
+            revert(0, 0)
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/contracts/asset-proxy/contracts/src/ERC721Proxy.sol b/contracts/asset-proxy/contracts/src/ERC721Proxy.sol
new file mode 100644
index 000000000..65b664b8b
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/ERC721Proxy.sol
@@ -0,0 +1,171 @@
+/*
+
+  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 "./MixinAuthorizable.sol";
+
+
+contract ERC721Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant internal PROXY_ID = bytes4(keccak256("ERC721Token(address,uint256)"));
+
+    // solhint-disable-next-line payable-fallback
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                // `transferFrom`.
+                // The function is marked `external`, so no abi decodeding is done for
+                // us. Instead, we expect the `calldata` memory to contain the
+                // following:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. offset to assetData (*)        |
+                // |          | 36     |         |   2. from                           |
+                // |          | 68     |         |   3. to                             |
+                // |          | 100    |         |   4. amount                         |
+                // | Data     |        |         | assetData:                          |
+                // |          | 132    | 32      | assetData Length                    |
+                // |          | 164    | **      | assetData Contents                  |
+                //
+                // (*): offset is computed from start of function parameters, so offset
+                //      by an additional 4 bytes in the calldata.
+                //
+                // (**): see table below to compute length of assetData Contents
+                //
+                // WARNING: The ABIv2 specification allows additional padding between
+                //          the Params and Data section. This will result in a larger
+                //          offset to assetData.
+
+                // Asset data itself is encoded as follows:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 2 * 32  | function parameters:                |
+                // |          | 4      | 12 + 20 |   1. token address                  |
+                // |          | 36     |         |   2. tokenId                        |
+                
+                // We construct calldata for the `token.transferFrom` ABI.
+                // The layout of this calldata is in the table below.
+                // 
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 3 * 32  | function parameters:                |
+                // |          | 4      |         |   1. from                           |
+                // |          | 36     |         |   2. to                             |
+                // |          | 68     |         |   3. tokenId                        |
+
+                // There exists only 1 of each token.
+                // require(amount == 1, "INVALID_AMOUNT")
+                if sub(calldataload(100), 1) {
+                    // Revert with `Error("INVALID_AMOUNT")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000000e494e56414c49445f414d4f554e540000000000000000000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFrom` selector.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(0, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // We copy the fields `from` and `to` in bulk
+                // from our own calldata to the new calldata.
+                calldatacopy(4, 36, 64)
+
+                // Copy `tokenId` field from our own calldata to the new calldata.
+                let assetDataOffset := calldataload(4)
+                calldatacopy(68, add(assetDataOffset, 72), 32)
+
+                /////// Call `token.transferFrom` using the calldata ///////
+                let token := calldataload(add(assetDataOffset, 40))
+                let success := call(
+                    gas,            // forward all gas
+                    token,          // call address of token contract
+                    0,              // don't send any ETH
+                    0,              // pointer to start of input
+                    100,            // length of input
+                    0,              // write output to null
+                    0               // output size is 0 bytes
+                )
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+
+            // Revert if undefined function is called
+            revert(0, 0)
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/contracts/asset-proxy/contracts/src/MixinAssetProxyDispatcher.sol b/contracts/asset-proxy/contracts/src/MixinAssetProxyDispatcher.sol
new file mode 100644
index 000000000..36c287ea3
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/MixinAssetProxyDispatcher.sol
@@ -0,0 +1,174 @@
+/*
+
+  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 "@0x/contracts-utils/contracts/src/Ownable.sol";
+import "./mixins/MAssetProxyDispatcher.sol";
+import "./interfaces/IAssetProxy.sol";
+
+
+contract MixinAssetProxyDispatcher is
+    Ownable,
+    MAssetProxyDispatcher
+{
+    // Mapping from Asset Proxy Id's to their respective Asset Proxy
+    mapping (bytes4 => IAssetProxy) public assetProxies;
+
+    /// @dev Registers an asset proxy to its asset proxy id.
+    ///      Once an asset proxy is registered, it cannot be unregistered.
+    /// @param assetProxy Address of new asset proxy to register.
+    function registerAssetProxy(address assetProxy)
+        external
+        onlyOwner
+    {
+        IAssetProxy assetProxyContract = IAssetProxy(assetProxy);
+
+        // Ensure that no asset proxy exists with current id.
+        bytes4 assetProxyId = assetProxyContract.getProxyId();
+        address currentAssetProxy = assetProxies[assetProxyId];
+        require(
+            currentAssetProxy == address(0),
+            "ASSET_PROXY_ALREADY_EXISTS"
+        );
+
+        // Add asset proxy and log registration.
+        assetProxies[assetProxyId] = assetProxyContract;
+        emit AssetProxyRegistered(
+            assetProxyId,
+            assetProxy
+        );
+    }
+
+    /// @dev Gets an asset proxy.
+    /// @param assetProxyId Id of the asset proxy.
+    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
+    function getAssetProxy(bytes4 assetProxyId)
+        external
+        view
+        returns (address)
+    {
+        return assetProxies[assetProxyId];
+    }
+
+    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the asset.
+    /// @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 assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        // Do nothing if no amount should be transferred.
+        if (amount > 0 && from != to) {
+            // Ensure assetData length is valid
+            require(
+                assetData.length > 3,
+                "LENGTH_GREATER_THAN_3_REQUIRED"
+            );
+            
+            // Lookup assetProxy. We do not use `LibBytes.readBytes4` for gas efficiency reasons.
+            bytes4 assetProxyId;
+            assembly {
+                assetProxyId := and(mload(
+                    add(assetData, 32)),
+                    0xFFFFFFFF00000000000000000000000000000000000000000000000000000000
+                )
+            }
+            address assetProxy = assetProxies[assetProxyId];
+
+            // Ensure that assetProxy exists
+            require(
+                assetProxy != address(0),
+                "ASSET_PROXY_DOES_NOT_EXIST"
+            );
+            
+            // We construct calldata for the `assetProxy.transferFrom` ABI.
+            // The layout of this calldata is in the table below.
+            // 
+            // | Area     | Offset | Length  | Contents                                    |
+            // | -------- |--------|---------|-------------------------------------------- |
+            // | Header   | 0      | 4       | function selector                           |
+            // | Params   |        | 4 * 32  | function parameters:                        |
+            // |          | 4      |         |   1. offset to assetData (*)                |
+            // |          | 36     |         |   2. from                                   |
+            // |          | 68     |         |   3. to                                     |
+            // |          | 100    |         |   4. amount                                 |
+            // | Data     |        |         | assetData:                                  |
+            // |          | 132    | 32      | assetData Length                            |
+            // |          | 164    | **      | assetData Contents                          |
+
+            assembly {
+                /////// Setup State ///////
+                // `cdStart` is the start of the calldata for `assetProxy.transferFrom` (equal to free memory ptr).
+                let cdStart := mload(64)
+                // `dataAreaLength` is the total number of words needed to store `assetData`
+                //  As-per the ABI spec, this value is padded up to the nearest multiple of 32,
+                //  and includes 32-bytes for length.
+                let dataAreaLength := and(add(mload(assetData), 63), 0xFFFFFFFFFFFE0)
+                // `cdEnd` is the end of the calldata for `assetProxy.transferFrom`.
+                let cdEnd := add(cdStart, add(132, dataAreaLength))
+
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFromSelector`.
+                // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+                mstore(cdStart, 0xa85e59e400000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // Each parameter is padded to 32-bytes. The entire Params Area is 128 bytes.
+                // Notes:
+                //   1. The offset to `assetData` is the length of the Params Area (128 bytes).
+                //   2. A 20-byte mask is applied to addresses to zero-out the unused bytes.
+                mstore(add(cdStart, 4), 128)
+                mstore(add(cdStart, 36), and(from, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(cdStart, 68), and(to, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(cdStart, 100), amount)
+                
+                /////// Setup Data Area ///////
+                // This area holds `assetData`.
+                let dataArea := add(cdStart, 132)
+                // solhint-disable-next-line no-empty-blocks
+                for {} lt(dataArea, cdEnd) {} {
+                    mstore(dataArea, mload(assetData))
+                    dataArea := add(dataArea, 32)
+                    assetData := add(assetData, 32)
+                }
+
+                /////// Call `assetProxy.transferFrom` using the constructed calldata ///////
+                let success := call(
+                    gas,                    // forward all gas
+                    assetProxy,             // call address of asset proxy
+                    0,                      // don't send any ETH
+                    cdStart,                // pointer to start of input
+                    sub(cdEnd, cdStart),    // length of input  
+                    cdStart,                // write output over input
+                    512                     // reserve 512 bytes for output
+                )
+                if iszero(success) {
+                    revert(cdStart, returndatasize())
+                }
+            }
+        }
+    }
+}
diff --git a/contracts/asset-proxy/contracts/src/MixinAuthorizable.sol b/contracts/asset-proxy/contracts/src/MixinAuthorizable.sol
new file mode 100644
index 000000000..ace820625
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/MixinAuthorizable.sol
@@ -0,0 +1,117 @@
+/*
+
+  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 "@0x/contracts-utils/contracts/src/Ownable.sol";
+import "./mixins/MAuthorizable.sol";
+
+
+contract MixinAuthorizable is
+    Ownable,
+    MAuthorizable
+{
+    /// @dev Only authorized addresses can invoke functions with this modifier.
+    modifier onlyAuthorized {
+        require(
+            authorized[msg.sender],
+            "SENDER_NOT_AUTHORIZED"
+        );
+        _;
+    }
+
+    mapping (address => bool) public authorized;
+    address[] public authorities;
+
+    /// @dev Authorizes an address.
+    /// @param target Address to authorize.
+    function addAuthorizedAddress(address target)
+        external
+        onlyOwner
+    {
+        require(
+            !authorized[target],
+            "TARGET_ALREADY_AUTHORIZED"
+        );
+
+        authorized[target] = true;
+        authorities.push(target);
+        emit AuthorizedAddressAdded(target, msg.sender);
+    }
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    function removeAuthorizedAddress(address target)
+        external
+        onlyOwner
+    {
+        require(
+            authorized[target],
+            "TARGET_NOT_AUTHORIZED"
+        );
+
+        delete authorized[target];
+        for (uint256 i = 0; i < authorities.length; i++) {
+            if (authorities[i] == target) {
+                authorities[i] = authorities[authorities.length - 1];
+                authorities.length -= 1;
+                break;
+            }
+        }
+        emit AuthorizedAddressRemoved(target, msg.sender);
+    }
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    /// @param index Index of target in authorities array.
+    function removeAuthorizedAddressAtIndex(
+        address target,
+        uint256 index
+    )
+        external
+        onlyOwner
+    {
+        require(
+            authorized[target],
+            "TARGET_NOT_AUTHORIZED"
+        );
+        require(
+            index < authorities.length,
+            "INDEX_OUT_OF_BOUNDS"
+        );
+        require(
+            authorities[index] == target,
+            "AUTHORIZED_ADDRESS_MISMATCH"
+        );
+
+        delete authorized[target];
+        authorities[index] = authorities[authorities.length - 1];
+        authorities.length -= 1;
+        emit AuthorizedAddressRemoved(target, msg.sender);
+    }
+
+    /// @dev Gets all authorized addresses.
+    /// @return Array of authorized addresses.
+    function getAuthorizedAddresses()
+        external
+        view
+        returns (address[] memory)
+    {
+        return authorities;
+    }
+}
diff --git a/contracts/asset-proxy/contracts/src/MultiAssetProxy.sol b/contracts/asset-proxy/contracts/src/MultiAssetProxy.sol
new file mode 100644
index 000000000..0b2cb4134
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/MultiAssetProxy.sol
@@ -0,0 +1,306 @@
+/*
+
+  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 "./MixinAssetProxyDispatcher.sol";
+import "./MixinAuthorizable.sol";
+
+
+contract MultiAssetProxy is
+    MixinAssetProxyDispatcher,
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant internal PROXY_ID = bytes4(keccak256("MultiAsset(uint256[],bytes[])"));
+
+    // solhint-disable-next-line payable-fallback
+    function ()
+        external
+    {
+        // NOTE: The below assembly assumes that clients do some input validation and that the input is properly encoded according to the AbiV2 specification.
+        // It is technically possible for inputs with very large lengths and offsets to cause overflows. However, this would make the calldata prohibitively
+        // expensive and we therefore do not check for overflows in these scenarios.
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                mstore(0, caller)
+                mstore(32, authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(0, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                // `transferFrom`.
+                // The function is marked `external`, so no abi decoding is done for
+                // us. Instead, we expect the `calldata` memory to contain the
+                // following:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. offset to assetData (*)        |
+                // |          | 36     |         |   2. from                           |
+                // |          | 68     |         |   3. to                             |
+                // |          | 100    |         |   4. amount                         |
+                // | Data     |        |         | assetData:                          |
+                // |          | 132    | 32      | assetData Length                    |
+                // |          | 164    | **      | assetData Contents                  |
+                //
+                // (*): offset is computed from start of function parameters, so offset
+                //      by an additional 4 bytes in the calldata.
+                //
+                // (**): see table below to compute length of assetData Contents
+                //
+                // WARNING: The ABIv2 specification allows additional padding between
+                //          the Params and Data section. This will result in a larger
+                //          offset to assetData.
+
+                // Load offset to `assetData`
+                let assetDataOffset := calldataload(4)
+
+                // Asset data itself is encoded as follows:
+                //
+                // | Area     | Offset      | Length  | Contents                            |
+                // |----------|-------------|---------|-------------------------------------|
+                // | Header   | 0           | 4       | assetProxyId                        |
+                // | Params   |             | 2 * 32  | function parameters:                |
+                // |          | 4           |         |   1. offset to amounts (*)          |
+                // |          | 36          |         |   2. offset to nestedAssetData (*)  |
+                // | Data     |             |         | amounts:                            |
+                // |          | 68          | 32      | amounts Length                      |
+                // |          | 100         | a       | amounts Contents                    | 
+                // |          |             |         | nestedAssetData:                    |
+                // |          | 100 + a     | 32      | nestedAssetData Length              |
+                // |          | 132 + a     | b       | nestedAssetData Contents (offsets)  |
+                // |          | 132 + a + b |         | nestedAssetData[0, ..., len]        |
+
+                // In order to find the offset to `amounts`, we must add:
+                // 4 (function selector)
+                // + assetDataOffset
+                // + 32 (assetData len)
+                // + 4 (assetProxyId)
+                let amountsOffset := calldataload(add(assetDataOffset, 40))
+
+                // In order to find the offset to `nestedAssetData`, we must add:
+                // 4 (function selector)
+                // + assetDataOffset
+                // + 32 (assetData len)
+                // + 4 (assetProxyId)
+                // + 32 (amounts offset)
+                let nestedAssetDataOffset := calldataload(add(assetDataOffset, 72))
+
+                // In order to find the start of the `amounts` contents, we must add: 
+                // 4 (function selector) 
+                // + assetDataOffset 
+                // + 32 (assetData len)
+                // + 4 (assetProxyId)
+                // + amountsOffset
+                // + 32 (amounts len)
+                let amountsContentsStart := add(assetDataOffset, add(amountsOffset, 72))
+
+                // Load number of elements in `amounts`
+                let amountsLen := calldataload(sub(amountsContentsStart, 32))
+
+                // In order to find the start of the `nestedAssetData` contents, we must add: 
+                // 4 (function selector) 
+                // + assetDataOffset 
+                // + 32 (assetData len)
+                // + 4 (assetProxyId)
+                // + nestedAssetDataOffset
+                // + 32 (nestedAssetData len)
+                let nestedAssetDataContentsStart := add(assetDataOffset, add(nestedAssetDataOffset, 72))
+
+                // Load number of elements in `nestedAssetData`
+                let nestedAssetDataLen := calldataload(sub(nestedAssetDataContentsStart, 32))
+
+                // Revert if number of elements in `amounts` differs from number of elements in `nestedAssetData`
+                if sub(amountsLen, nestedAssetDataLen) {
+                    // Revert with `Error("LENGTH_MISMATCH")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000000f4c454e4754485f4d49534d4154434800000000000000000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                // Copy `transferFrom` selector, offset to `assetData`, `from`, and `to` from calldata to memory
+                calldatacopy(
+                    0,   // memory can safely be overwritten from beginning
+                    0,   // start of calldata
+                    100  // length of selector (4) and 3 params (32 * 3)
+                )
+
+                // Overwrite existing offset to `assetData` with our own
+                mstore(4, 128)
+                
+                // Load `amount`
+                let amount := calldataload(100)
+        
+                // Calculate number of bytes in `amounts` contents
+                let amountsByteLen := mul(amountsLen, 32)
+
+                // Initialize `assetProxyId` and `assetProxy` to 0
+                let assetProxyId := 0
+                let assetProxy := 0
+
+                // Loop through `amounts` and `nestedAssetData`, calling `transferFrom` for each respective element
+                for {let i := 0} lt(i, amountsByteLen) {i := add(i, 32)} {
+
+                    // Calculate the total amount
+                    let amountsElement := calldataload(add(amountsContentsStart, i))
+                    let totalAmount := mul(amountsElement, amount)
+
+                    // Revert if `amount` != 0 and multiplication resulted in an overflow 
+                    if iszero(or(
+                        iszero(amount),
+                        eq(div(totalAmount, amount), amountsElement)
+                    )) {
+                        // Revert with `Error("UINT256_OVERFLOW")`
+                        mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                        mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                        mstore(64, 0x0000001055494e543235365f4f564552464c4f57000000000000000000000000)
+                        mstore(96, 0)
+                        revert(0, 100)
+                    }
+
+                    // Write `totalAmount` to memory
+                    mstore(100, totalAmount)
+
+                    // Load offset to `nestedAssetData[i]`
+                    let nestedAssetDataElementOffset := calldataload(add(nestedAssetDataContentsStart, i))
+
+                    // In order to find the start of the `nestedAssetData[i]` contents, we must add:
+                    // 4 (function selector) 
+                    // + assetDataOffset 
+                    // + 32 (assetData len)
+                    // + 4 (assetProxyId)
+                    // + nestedAssetDataOffset
+                    // + 32 (nestedAssetData len)
+                    // + nestedAssetDataElementOffset
+                    // + 32 (nestedAssetDataElement len)
+                    let nestedAssetDataElementContentsStart := add(assetDataOffset, add(nestedAssetDataOffset, add(nestedAssetDataElementOffset, 104)))
+
+                    // Load length of `nestedAssetData[i]`
+                    let nestedAssetDataElementLenStart := sub(nestedAssetDataElementContentsStart, 32)
+                    let nestedAssetDataElementLen := calldataload(nestedAssetDataElementLenStart)
+
+                    // Revert if the `nestedAssetData` does not contain a 4 byte `assetProxyId`
+                    if lt(nestedAssetDataElementLen, 4) {
+                        // Revert with `Error("LENGTH_GREATER_THAN_3_REQUIRED")`
+                        mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                        mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                        mstore(64, 0x0000001e4c454e4754485f475245415445525f5448414e5f335f524551554952)
+                        mstore(96, 0x4544000000000000000000000000000000000000000000000000000000000000)
+                        revert(0, 100)
+                    }
+
+                    // Load AssetProxy id
+                    let currentAssetProxyId := and(
+                        calldataload(nestedAssetDataElementContentsStart),
+                        0xffffffff00000000000000000000000000000000000000000000000000000000
+                    )
+
+                    // Only load `assetProxy` if `currentAssetProxyId` does not equal `assetProxyId`
+                    // We do not need to check if `currentAssetProxyId` is 0 since `assetProxy` is also initialized to 0
+                    if sub(currentAssetProxyId, assetProxyId) {
+                        // Update `assetProxyId`
+                        assetProxyId := currentAssetProxyId
+                        // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                        // where k is the key left padded to 32 bytes and p is the storage slot
+                        mstore(132, assetProxyId)
+                        mstore(164, assetProxies_slot)
+                        assetProxy := sload(keccak256(132, 64))
+                    }
+                    
+                    // Revert if AssetProxy with given id does not exist
+                    if iszero(assetProxy) {
+                        // Revert with `Error("ASSET_PROXY_DOES_NOT_EXIST")`
+                        mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                        mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                        mstore(64, 0x0000001a41535345545f50524f58595f444f45535f4e4f545f45584953540000)
+                        mstore(96, 0)
+                        revert(0, 100)
+                    }
+    
+                    // Copy `nestedAssetData[i]` from calldata to memory
+                    calldatacopy(
+                        132,                                // memory slot after `amounts[i]`
+                        nestedAssetDataElementLenStart,     // location of `nestedAssetData[i]` in calldata
+                        add(nestedAssetDataElementLen, 32)  // `nestedAssetData[i].length` plus 32 byte length
+                    )
+
+                    // call `assetProxy.transferFrom`
+                    let success := call(
+                        gas,                                    // forward all gas
+                        assetProxy,                             // call address of asset proxy
+                        0,                                      // don't send any ETH
+                        0,                                      // pointer to start of input
+                        add(164, nestedAssetDataElementLen),    // length of input  
+                        0,                                      // write output over memory that won't be reused
+                        0                                       // don't copy output to memory
+                    )
+
+                    // Revert with reason given by AssetProxy if `transferFrom` call failed
+                    if iszero(success) {
+                        returndatacopy(
+                            0,                // copy to memory at 0
+                            0,                // copy from return data at 0
+                            returndatasize()  // copy all return data
+                        )
+                        revert(0, returndatasize())
+                    }
+                }
+
+                // Return if no `transferFrom` calls reverted
+                return(0, 0)
+            }
+
+            // Revert if undefined function is called
+            revert(0, 0)
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/contracts/asset-proxy/contracts/src/interfaces/IAssetData.sol b/contracts/asset-proxy/contracts/src/interfaces/IAssetData.sol
new file mode 100644
index 000000000..a130e615f
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/interfaces/IAssetData.sol
@@ -0,0 +1,44 @@
+/*
+
+  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.
+
+*/
+
+// solhint-disable
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+
+// @dev Interface of the asset proxy's assetData.
+// The asset proxies take an ABI encoded `bytes assetData` as argument.
+// This argument is ABI encoded as one of the methods of this interface.
+interface IAssetData {
+
+    function ERC20Token(address tokenContract)
+        external;
+    
+    function ERC721Token(
+        address tokenContract,
+        uint256 tokenId
+    )
+        external;
+
+    function MultiAsset(
+        uint256[] amounts,
+        bytes[] nestedAssetData
+    )
+        external;
+    
+}
diff --git a/contracts/asset-proxy/contracts/src/interfaces/IAssetProxy.sol b/contracts/asset-proxy/contracts/src/interfaces/IAssetProxy.sol
new file mode 100644
index 000000000..706412dd0
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/interfaces/IAssetProxy.sol
@@ -0,0 +1,46 @@
+/*
+
+  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 "./IAuthorizable.sol";
+
+
+contract IAssetProxy is
+    IAuthorizable
+{
+    /// @dev Transfers assets. Either succeeds or throws.
+    /// @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 assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        external;
+    
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4);
+}
diff --git a/contracts/asset-proxy/contracts/src/interfaces/IAssetProxyDispatcher.sol b/contracts/asset-proxy/contracts/src/interfaces/IAssetProxyDispatcher.sol
new file mode 100644
index 000000000..b73881c07
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/interfaces/IAssetProxyDispatcher.sol
@@ -0,0 +1,37 @@
+/*
+
+  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 IAssetProxyDispatcher {
+
+    /// @dev Registers an asset proxy to its asset proxy id.
+    ///      Once an asset proxy is registered, it cannot be unregistered.
+    /// @param assetProxy Address of new asset proxy to register.
+    function registerAssetProxy(address assetProxy)
+        external;
+
+    /// @dev Gets an asset proxy.
+    /// @param assetProxyId Id of the asset proxy.
+    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
+    function getAssetProxy(bytes4 assetProxyId)
+        external
+        view
+        returns (address);
+}
diff --git a/contracts/asset-proxy/contracts/src/interfaces/IAuthorizable.sol b/contracts/asset-proxy/contracts/src/interfaces/IAuthorizable.sol
new file mode 100644
index 000000000..0df654711
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/interfaces/IAuthorizable.sol
@@ -0,0 +1,52 @@
+/*
+
+  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 "@0x/contracts-utils/contracts/src/interfaces/IOwnable.sol";
+
+
+contract IAuthorizable is
+    IOwnable
+{
+    /// @dev Authorizes an address.
+    /// @param target Address to authorize.
+    function addAuthorizedAddress(address target)
+        external;
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    function removeAuthorizedAddress(address target)
+        external;
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    /// @param index Index of target in authorities array.
+    function removeAuthorizedAddressAtIndex(
+        address target,
+        uint256 index
+    )
+        external;
+    
+    /// @dev Gets all authorized addresses.
+    /// @return Array of authorized addresses.
+    function getAuthorizedAddresses()
+        external
+        view
+        returns (address[] memory);
+}
diff --git a/contracts/asset-proxy/contracts/src/mixins/MAssetProxyDispatcher.sol b/contracts/asset-proxy/contracts/src/mixins/MAssetProxyDispatcher.sol
new file mode 100644
index 000000000..0ae555dda
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/mixins/MAssetProxyDispatcher.sol
@@ -0,0 +1,45 @@
+/*
+
+  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 "../interfaces/IAssetProxyDispatcher.sol";
+
+
+contract MAssetProxyDispatcher is
+    IAssetProxyDispatcher
+{
+    // Logs registration of new asset proxy
+    event AssetProxyRegistered(
+        bytes4 id,              // Id of new registered AssetProxy.
+        address assetProxy      // Address of new registered AssetProxy.
+    );
+
+    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the asset.
+    /// @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 assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal;
+}
diff --git a/contracts/asset-proxy/contracts/src/mixins/MAuthorizable.sol b/contracts/asset-proxy/contracts/src/mixins/MAuthorizable.sol
new file mode 100644
index 000000000..c9c07e788
--- /dev/null
+++ b/contracts/asset-proxy/contracts/src/mixins/MAuthorizable.sol
@@ -0,0 +1,41 @@
+/*
+
+  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 "../interfaces/IAuthorizable.sol";
+
+
+contract MAuthorizable is
+    IAuthorizable
+{
+    // Event logged when a new address is authorized.
+    event AuthorizedAddressAdded(
+        address indexed target,
+        address indexed caller
+    );
+
+    // Event logged when a currently authorized address is unauthorized.
+    event AuthorizedAddressRemoved(
+        address indexed target,
+        address indexed caller
+    );
+
+    /// @dev Only authorized addresses can invoke functions with this modifier.
+    modifier onlyAuthorized { revert(); _; }
+}
diff --git a/contracts/asset-proxy/package.json b/contracts/asset-proxy/package.json
new file mode 100644
index 000000000..360fdab75
--- /dev/null
+++ b/contracts/asset-proxy/package.json
@@ -0,0 +1,82 @@
+{
+    "name": "@0x/contracts-asset-proxy",
+    "version": "1.0.0",
+    "engines": {
+        "node": ">=6.12"
+    },
+    "description": "Smart contract components of 0x protocol",
+    "main": "lib/src/index.js",
+    "directories": {
+        "test": "test"
+    },
+    "scripts": {
+        "build": "yarn pre_build && tsc -b",
+        "build:ci": "yarn build",
+        "pre_build": "run-s compile generate_contract_wrappers",
+        "test": "yarn run_mocha",
+        "rebuild_and_test": "run-s build test",
+        "test:coverage": "SOLIDITY_COVERAGE=true run-s build run_mocha coverage:report:text coverage:report:lcov",
+        "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
+        "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
+        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
+        "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
+        "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
+        "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
+        "coverage:report:text": "istanbul report text",
+        "coverage:report:html": "istanbul report html && open coverage/index.html",
+        "profiler:report:html": "istanbul report html && open coverage/index.html",
+        "coverage:report:lcov": "istanbul report lcov",
+        "test:circleci": "yarn test",
+        "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol"
+    },
+    "config": {
+        "abis": "generated-artifacts/@(ERC20Proxy|ERC721Proxy|IAssetData|IAssetProxy|IAuthorizable|MixinAuthorizable|MultiAssetProxy).json"
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/0xProject/0x-monorepo.git"
+    },
+    "license": "Apache-2.0",
+    "bugs": {
+        "url": "https://github.com/0xProject/0x-monorepo/issues"
+    },
+    "homepage": "https://github.com/0xProject/0x-monorepo/contracts/protocol/README.md",
+    "devDependencies": {
+        "@0x/abi-gen": "^1.0.22",
+        "@0x/dev-utils": "^1.0.24",
+        "@0x/sol-compiler": "^2.0.2",
+        "@0x/tslint-config": "^2.0.2",
+        "@types/lodash": "4.14.104",
+        "@types/node": "*",
+        "chai": "^4.0.1",
+        "chai-as-promised": "^7.1.0",
+        "chai-bignumber": "^3.0.0",
+        "dirty-chai": "^2.0.1",
+        "make-promises-safe": "^1.1.0",
+        "mocha": "^4.1.0",
+        "npm-run-all": "^4.1.2",
+        "shx": "^0.2.2",
+        "solhint": "^1.4.1",
+        "tslint": "5.11.0",
+        "typescript": "3.0.1"
+    },
+    "dependencies": {
+        "@0x/base-contract": "^3.0.13",
+        "@0x/contracts-test-utils": "^2.0.1",
+        "@0x/contracts-erc20": "1.0.0",
+        "@0x/contracts-erc721": "1.0.0",
+        "@0x/contracts-utils": "3.0.0",
+        "@0x/order-utils": "^3.1.2",
+        "@0x/types": "^1.5.2",
+        "@0x/typescript-typings": "^3.0.8",
+        "@0x/utils": "^3.0.1",
+        "@0x/web3-wrapper": "^3.2.4",
+        "ethereum-types": "^1.1.6",
+        "lodash": "^4.17.5"
+    },
+    "publishConfig": {
+        "access": "public"
+    }
+}
diff --git a/contracts/asset-proxy/src/artifacts/index.ts b/contracts/asset-proxy/src/artifacts/index.ts
new file mode 100644
index 000000000..7f3060815
--- /dev/null
+++ b/contracts/asset-proxy/src/artifacts/index.ts
@@ -0,0 +1,19 @@
+import { ContractArtifact } from 'ethereum-types';
+
+import * as ERC20Proxy from '../../generated-artifacts/ERC20Proxy.json';
+import * as ERC721Proxy from '../../generated-artifacts/ERC721Proxy.json';
+import * as IAssetData from '../../generated-artifacts/IAssetData.json';
+import * as IAssetProxy from '../../generated-artifacts/IAssetProxy.json';
+import * as IAuthorizable from '../../generated-artifacts/IAuthorizable.json';
+import * as MixinAuthorizable from '../../generated-artifacts/MixinAuthorizable.json';
+import * as MultiAssetProxy from '../../generated-artifacts/MultiAssetProxy.json';
+
+export const artifacts = {
+    IAuthorizable: IAuthorizable as ContractArtifact,
+    IAssetData: IAssetData as ContractArtifact,
+    IAssetProxy: IAssetProxy as ContractArtifact,
+    ERC20Proxy: ERC20Proxy as ContractArtifact,
+    ERC721Proxy: ERC721Proxy as ContractArtifact,
+    MixinAuthorizable: MixinAuthorizable as ContractArtifact,
+    MultiAssetProxy: MultiAssetProxy as ContractArtifact,
+};
diff --git a/contracts/asset-proxy/src/index.ts b/contracts/asset-proxy/src/index.ts
new file mode 100644
index 000000000..ba813e7ca
--- /dev/null
+++ b/contracts/asset-proxy/src/index.ts
@@ -0,0 +1,3 @@
+export * from './artifacts';
+export * from './wrappers';
+export * from '../test/utils';
diff --git a/contracts/asset-proxy/src/wrappers/index.ts b/contracts/asset-proxy/src/wrappers/index.ts
new file mode 100644
index 000000000..6aecbc086
--- /dev/null
+++ b/contracts/asset-proxy/src/wrappers/index.ts
@@ -0,0 +1,7 @@
+export * from '../../generated-wrappers/i_asset_data';
+export * from '../../generated-wrappers/i_asset_proxy';
+export * from '../../generated-wrappers/erc20_proxy';
+export * from '../../generated-wrappers/erc721_proxy';
+export * from '../../generated-wrappers/mixin_authorizable';
+export * from '../../generated-wrappers/multi_asset_proxy';
+export * from '../../generated-wrappers/i_authorizable';
diff --git a/contracts/asset-proxy/test/authorizable.ts b/contracts/asset-proxy/test/authorizable.ts
new file mode 100644
index 000000000..087121235
--- /dev/null
+++ b/contracts/asset-proxy/test/authorizable.ts
@@ -0,0 +1,210 @@
+import {
+    chaiSetup,
+    constants,
+    expectTransactionFailedAsync,
+    provider,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { RevertReason } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import * as chai from 'chai';
+import * as _ from 'lodash';
+
+import { artifacts, MixinAuthorizableContract } from '../src';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('Authorizable', () => {
+    let owner: string;
+    let notOwner: string;
+    let address: string;
+    let authorizable: MixinAuthorizableContract;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        [owner, address, notOwner] = _.slice(accounts, 0, 3);
+        authorizable = await MixinAuthorizableContract.deployFrom0xArtifactAsync(
+            artifacts.MixinAuthorizable,
+            provider,
+            txDefaults,
+        );
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('addAuthorizedAddress', () => {
+        it('should throw if not called by owner', async () => {
+            return expectTransactionFailedAsync(
+                authorizable.addAuthorizedAddress.sendTransactionAsync(notOwner, { from: notOwner }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+        it('should allow owner to add an authorized address', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isAuthorized = await authorizable.authorized.callAsync(address);
+            expect(isAuthorized).to.be.true();
+        });
+        it('should throw if owner attempts to authorize a duplicate address', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            return expectTransactionFailedAsync(
+                authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                RevertReason.TargetAlreadyAuthorized,
+            );
+        });
+    });
+
+    describe('removeAuthorizedAddress', () => {
+        it('should throw if not called by owner', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            return expectTransactionFailedAsync(
+                authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
+                    from: notOwner,
+                }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+
+        it('should allow owner to remove an authorized address', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isAuthorized = await authorizable.authorized.callAsync(address);
+            expect(isAuthorized).to.be.false();
+        });
+
+        it('should throw if owner attempts to remove an address that is not authorized', async () => {
+            return expectTransactionFailedAsync(
+                authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
+                    from: owner,
+                }),
+                RevertReason.TargetNotAuthorized,
+            );
+        });
+    });
+
+    describe('removeAuthorizedAddressAtIndex', () => {
+        it('should throw if not called by owner', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const index = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: notOwner,
+                }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+        it('should throw if index is >= authorities.length', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const index = new BigNumber(1);
+            return expectTransactionFailedAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: owner,
+                }),
+                RevertReason.IndexOutOfBounds,
+            );
+        });
+        it('should throw if owner attempts to remove an address that is not authorized', async () => {
+            const index = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: owner,
+                }),
+                RevertReason.TargetNotAuthorized,
+            );
+        });
+        it('should throw if address at index does not match target', async () => {
+            const address1 = address;
+            const address2 = notOwner;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address1, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address2, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const address1Index = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address2, address1Index, {
+                    from: owner,
+                }),
+                RevertReason.AuthorizedAddressMismatch,
+            );
+        });
+        it('should allow owner to remove an authorized address', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const index = new BigNumber(0);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isAuthorized = await authorizable.authorized.callAsync(address);
+            expect(isAuthorized).to.be.false();
+        });
+    });
+
+    describe('getAuthorizedAddresses', () => {
+        it('should return all authorized addresses', async () => {
+            const initial = await authorizable.getAuthorizedAddresses.callAsync();
+            expect(initial).to.have.length(0);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const afterAdd = await authorizable.getAuthorizedAddresses.callAsync();
+            expect(afterAdd).to.have.length(1);
+            expect(afterAdd).to.include(address);
+
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const afterRemove = await authorizable.getAuthorizedAddresses.callAsync();
+            expect(afterRemove).to.have.length(0);
+        });
+    });
+});
diff --git a/contracts/asset-proxy/test/global_hooks.ts b/contracts/asset-proxy/test/global_hooks.ts
new file mode 100644
index 000000000..f8ace376a
--- /dev/null
+++ b/contracts/asset-proxy/test/global_hooks.ts
@@ -0,0 +1,17 @@
+import { env, EnvVars } from '@0x/dev-utils';
+
+import { coverage, profiler, provider } from '@0x/contracts-test-utils';
+before('start web3 provider', () => {
+    provider.start();
+});
+after('generate coverage report', async () => {
+    if (env.parseBoolean(EnvVars.SolidityCoverage)) {
+        const coverageSubprovider = coverage.getCoverageSubproviderSingleton();
+        await coverageSubprovider.writeCoverageAsync();
+    }
+    if (env.parseBoolean(EnvVars.SolidityProfiler)) {
+        const profilerSubprovider = profiler.getProfilerSubproviderSingleton();
+        await profilerSubprovider.writeProfilerOutputAsync();
+    }
+    provider.stop();
+});
diff --git a/contracts/asset-proxy/test/proxies.ts b/contracts/asset-proxy/test/proxies.ts
new file mode 100644
index 000000000..797787135
--- /dev/null
+++ b/contracts/asset-proxy/test/proxies.ts
@@ -0,0 +1,1291 @@
+import {
+    artifacts as erc20Artifacts,
+    DummyERC20TokenContract,
+    DummyERC20TokenTransferEventArgs,
+    DummyMultipleReturnERC20TokenContract,
+    DummyNoReturnERC20TokenContract,
+} from '@0x/contracts-erc20';
+import {
+    artifacts as erc721Artifacts,
+    DummyERC721ReceiverContract,
+    DummyERC721TokenContract,
+} from '@0x/contracts-erc721';
+import {
+    chaiSetup,
+    constants,
+    expectTransactionFailedAsync,
+    expectTransactionFailedWithoutReasonAsync,
+    LogDecoder,
+    provider,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils } from '@0x/order-utils';
+import { RevertReason } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import * as chai from 'chai';
+import { LogWithDecodedArgs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import {
+    artifacts,
+    ERC20ProxyContract,
+    ERC20Wrapper,
+    ERC721ProxyContract,
+    ERC721Wrapper,
+    IAssetDataContract,
+    IAssetProxyContract,
+    MultiAssetProxyContract,
+} from '../src';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+const assetProxyInterface = new IAssetProxyContract(
+    artifacts.IAssetProxy.compilerOutput.abi,
+    constants.NULL_ADDRESS,
+    provider,
+);
+const assetDataInterface = new IAssetDataContract(
+    artifacts.IAssetData.compilerOutput.abi,
+    constants.NULL_ADDRESS,
+    provider,
+);
+
+// tslint:disable:no-unnecessary-type-assertion
+describe('Asset Transfer Proxies', () => {
+    let owner: string;
+    let notAuthorized: string;
+    let authorized: string;
+    let fromAddress: string;
+    let toAddress: string;
+
+    let erc20TokenA: DummyERC20TokenContract;
+    let erc20TokenB: DummyERC20TokenContract;
+    let erc721TokenA: DummyERC721TokenContract;
+    let erc721TokenB: DummyERC721TokenContract;
+    let erc721Receiver: DummyERC721ReceiverContract;
+    let erc20Proxy: ERC20ProxyContract;
+    let erc721Proxy: ERC721ProxyContract;
+    let noReturnErc20Token: DummyNoReturnERC20TokenContract;
+    let multipleReturnErc20Token: DummyMultipleReturnERC20TokenContract;
+    let multiAssetProxy: MultiAssetProxyContract;
+
+    let erc20Wrapper: ERC20Wrapper;
+    let erc721Wrapper: ERC721Wrapper;
+    let erc721AFromTokenId: BigNumber;
+    let erc721BFromTokenId: BigNumber;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        const usedAddresses = ([owner, notAuthorized, authorized, fromAddress, toAddress] = _.slice(accounts, 0, 5));
+
+        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+        erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
+
+        // Deploy AssetProxies
+        erc20Proxy = await erc20Wrapper.deployProxyAsync();
+        erc721Proxy = await erc721Wrapper.deployProxyAsync();
+        multiAssetProxy = await MultiAssetProxyContract.deployFrom0xArtifactAsync(
+            artifacts.MultiAssetProxy,
+            provider,
+            txDefaults,
+        );
+
+        // Configure ERC20Proxy
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(authorized, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(multiAssetProxy.address, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+
+        // Configure ERC721Proxy
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(authorized, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(multiAssetProxy.address, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+
+        // Configure MultiAssetProxy
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await multiAssetProxy.addAuthorizedAddress.sendTransactionAsync(authorized, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await multiAssetProxy.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await multiAssetProxy.registerAssetProxy.sendTransactionAsync(erc721Proxy.address, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+
+        // Deploy and configure ERC20 tokens
+        const numDummyErc20ToDeploy = 2;
+        [erc20TokenA, erc20TokenB] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        noReturnErc20Token = await DummyNoReturnERC20TokenContract.deployFrom0xArtifactAsync(
+            erc20Artifacts.DummyNoReturnERC20Token,
+            provider,
+            txDefaults,
+            constants.DUMMY_TOKEN_NAME,
+            constants.DUMMY_TOKEN_SYMBOL,
+            constants.DUMMY_TOKEN_DECIMALS,
+            constants.DUMMY_TOKEN_TOTAL_SUPPLY,
+        );
+        multipleReturnErc20Token = await DummyMultipleReturnERC20TokenContract.deployFrom0xArtifactAsync(
+            erc20Artifacts.DummyMultipleReturnERC20Token,
+            provider,
+            txDefaults,
+            constants.DUMMY_TOKEN_NAME,
+            constants.DUMMY_TOKEN_SYMBOL,
+            constants.DUMMY_TOKEN_DECIMALS,
+            constants.DUMMY_TOKEN_TOTAL_SUPPLY,
+        );
+
+        await erc20Wrapper.setBalancesAndAllowancesAsync();
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await noReturnErc20Token.setBalance.sendTransactionAsync(fromAddress, constants.INITIAL_ERC20_BALANCE),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await noReturnErc20Token.approve.sendTransactionAsync(
+                erc20Proxy.address,
+                constants.INITIAL_ERC20_ALLOWANCE,
+                { from: fromAddress },
+            ),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await multipleReturnErc20Token.setBalance.sendTransactionAsync(
+                fromAddress,
+                constants.INITIAL_ERC20_BALANCE,
+            ),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await multipleReturnErc20Token.approve.sendTransactionAsync(
+                erc20Proxy.address,
+                constants.INITIAL_ERC20_ALLOWANCE,
+                { from: fromAddress },
+            ),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+
+        // Deploy and configure ERC721 tokens and receiver
+        [erc721TokenA, erc721TokenB] = await erc721Wrapper.deployDummyTokensAsync();
+        erc721Receiver = await DummyERC721ReceiverContract.deployFrom0xArtifactAsync(
+            erc721Artifacts.DummyERC721Receiver,
+            provider,
+            txDefaults,
+        );
+
+        await erc721Wrapper.setBalancesAndAllowancesAsync();
+        const erc721Balances = await erc721Wrapper.getBalancesAsync();
+        erc721AFromTokenId = erc721Balances[fromAddress][erc721TokenA.address][0];
+        erc721BFromTokenId = erc721Balances[fromAddress][erc721TokenB.address][0];
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    describe('ERC20Proxy', () => {
+        it('should revert if undefined function is called', async () => {
+            const undefinedSelector = '0x01020304';
+            await expectTransactionFailedWithoutReasonAsync(
+                web3Wrapper.sendTransactionAsync({
+                    from: owner,
+                    to: erc20Proxy.address,
+                    value: constants.ZERO_AMOUNT,
+                    data: undefinedSelector,
+                }),
+            );
+        });
+        it('should have an id of 0xf47261b0', async () => {
+            const proxyId = await erc20Proxy.getProxyId.callAsync();
+            const expectedProxyId = '0xf47261b0';
+            expect(proxyId).to.equal(expectedProxyId);
+        });
+        describe('transferFrom', () => {
+            it('should successfully transfer tokens', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                // Perform a transfer from fromAddress to toAddress
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Verify transfer was successful
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(amount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(amount),
+                );
+            });
+
+            it('should successfully transfer tokens that do not return a value', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(noReturnErc20Token.address);
+                // Perform a transfer from fromAddress to toAddress
+                const initialFromBalance = await noReturnErc20Token.balanceOf.callAsync(fromAddress);
+                const initialToBalance = await noReturnErc20Token.balanceOf.callAsync(toAddress);
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Verify transfer was successful
+                const newFromBalance = await noReturnErc20Token.balanceOf.callAsync(fromAddress);
+                const newToBalance = await noReturnErc20Token.balanceOf.callAsync(toAddress);
+                expect(newFromBalance).to.be.bignumber.equal(initialFromBalance.minus(amount));
+                expect(newToBalance).to.be.bignumber.equal(initialToBalance.plus(amount));
+            });
+
+            it('should successfully transfer tokens and ignore extra assetData', async () => {
+                // Construct ERC20 asset data
+                const extraData = '0102030405060708';
+                const encodedAssetData = `${assetDataUtils.encodeERC20AssetData(erc20TokenA.address)}${extraData}`;
+                // Perform a transfer from fromAddress to toAddress
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Verify transfer was successful
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(amount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(amount),
+                );
+            });
+
+            it('should do nothing if transferring 0 amount of a token', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                // Perform a transfer from fromAddress to toAddress
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const amount = new BigNumber(0);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Verify transfer was successful
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address],
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address],
+                );
+            });
+
+            it('should revert if allowances are too low', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                // Create allowance less than transfer amount. Set allowance on proxy.
+                const allowance = new BigNumber(0);
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc20TokenA.approve.sendTransactionAsync(erc20Proxy.address, allowance, {
+                        from: fromAddress,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                // Perform a transfer; expect this to fail.
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.TransferFailed,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances).to.deep.equal(erc20Balances);
+            });
+
+            it('should revert if allowances are too low and token does not return a value', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(noReturnErc20Token.address);
+                // Create allowance less than transfer amount. Set allowance on proxy.
+                const allowance = new BigNumber(0);
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await noReturnErc20Token.approve.sendTransactionAsync(erc20Proxy.address, allowance, {
+                        from: fromAddress,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const initialFromBalance = await noReturnErc20Token.balanceOf.callAsync(fromAddress);
+                const initialToBalance = await noReturnErc20Token.balanceOf.callAsync(toAddress);
+                // Perform a transfer; expect this to fail.
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.TransferFailed,
+                );
+                const newFromBalance = await noReturnErc20Token.balanceOf.callAsync(fromAddress);
+                const newToBalance = await noReturnErc20Token.balanceOf.callAsync(toAddress);
+                expect(newFromBalance).to.be.bignumber.equal(initialFromBalance);
+                expect(newToBalance).to.be.bignumber.equal(initialToBalance);
+            });
+
+            it('should revert if caller is not authorized', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: notAuthorized,
+                    }),
+                    RevertReason.SenderNotAuthorized,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances).to.deep.equal(erc20Balances);
+            });
+
+            it('should revert if token returns more than 32 bytes', async () => {
+                // Construct ERC20 asset data
+                const encodedAssetData = assetDataUtils.encodeERC20AssetData(multipleReturnErc20Token.address);
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                const initialFromBalance = await multipleReturnErc20Token.balanceOf.callAsync(fromAddress);
+                const initialToBalance = await multipleReturnErc20Token.balanceOf.callAsync(toAddress);
+                // Perform a transfer; expect this to fail.
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.TransferFailed,
+                );
+                const newFromBalance = await multipleReturnErc20Token.balanceOf.callAsync(fromAddress);
+                const newToBalance = await multipleReturnErc20Token.balanceOf.callAsync(toAddress);
+                expect(newFromBalance).to.be.bignumber.equal(initialFromBalance);
+                expect(newToBalance).to.be.bignumber.equal(initialToBalance);
+            });
+        });
+    });
+
+    describe('ERC721Proxy', () => {
+        it('should revert if undefined function is called', async () => {
+            const undefinedSelector = '0x01020304';
+            await expectTransactionFailedWithoutReasonAsync(
+                web3Wrapper.sendTransactionAsync({
+                    from: owner,
+                    to: erc721Proxy.address,
+                    value: constants.ZERO_AMOUNT,
+                    data: undefinedSelector,
+                }),
+            );
+        });
+        it('should have an id of 0x02571792', async () => {
+            const proxyId = await erc721Proxy.getProxyId.callAsync();
+            const expectedProxyId = '0x02571792';
+            expect(proxyId).to.equal(expectedProxyId);
+        });
+        describe('transferFrom', () => {
+            it('should successfully transfer tokens', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Verify transfer was successful
+                const newOwnerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwnerFromAsset).to.be.bignumber.equal(toAddress);
+            });
+
+            it('should successfully transfer tokens and ignore extra assetData', async () => {
+                // Construct ERC721 asset data
+                const extraData = '0102030405060708';
+                const encodedAssetData = `${assetDataUtils.encodeERC721AssetData(
+                    erc721TokenA.address,
+                    erc721AFromTokenId,
+                )}${extraData}`;
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Verify transfer was successful
+                const newOwnerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwnerFromAsset).to.be.bignumber.equal(toAddress);
+            });
+
+            it('should not call onERC721Received when transferring to a smart contract', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    erc721Receiver.address,
+                    amount,
+                );
+                const logDecoder = new LogDecoder(web3Wrapper, { ...artifacts, ...erc721Artifacts });
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: authorized,
+                        gas: constants.MAX_TRANSFER_FROM_GAS,
+                    }),
+                );
+                // Verify that no log was emitted by erc721 receiver
+                expect(tx.logs.length).to.be.equal(1);
+                // Verify transfer was successful
+                const newOwnerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwnerFromAsset).to.be.bignumber.equal(erc721Receiver.address);
+            });
+
+            it('should revert if transferring 0 amount of a token', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(0);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.InvalidAmount,
+                );
+                const newOwner = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwner).to.be.equal(ownerFromAsset);
+            });
+
+            it('should revert if transferring > 1 amount of a token', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(500);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.InvalidAmount,
+                );
+                const newOwner = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwner).to.be.equal(ownerFromAsset);
+            });
+
+            it('should revert if allowances are too low', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Remove transfer approval for fromAddress.
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc721TokenA.approve.sendTransactionAsync(constants.NULL_ADDRESS, erc721AFromTokenId, {
+                        from: fromAddress,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                // Perform a transfer; expect this to fail.
+                const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.TransferFailed,
+                );
+                const newOwner = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwner).to.be.equal(ownerFromAsset);
+            });
+
+            it('should revert if caller is not authorized', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                // Verify pre-condition
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                // Perform a transfer from fromAddress to toAddress
+                const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    fromAddress,
+                    toAddress,
+                    amount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: notAuthorized,
+                    }),
+                    RevertReason.SenderNotAuthorized,
+                );
+                const newOwner = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwner).to.be.equal(ownerFromAsset);
+            });
+        });
+    });
+    describe('MultiAssetProxy', () => {
+        it('should revert if undefined function is called', async () => {
+            const undefinedSelector = '0x01020304';
+            await expectTransactionFailedWithoutReasonAsync(
+                web3Wrapper.sendTransactionAsync({
+                    from: owner,
+                    to: multiAssetProxy.address,
+                    value: constants.ZERO_AMOUNT,
+                    data: undefinedSelector,
+                }),
+            );
+        });
+        it('should have an id of 0x94cfcdd7', async () => {
+            const proxyId = await multiAssetProxy.getProxyId.callAsync();
+            // first 4 bytes of `keccak256('MultiAsset(uint256[],bytes[])')`
+            const expectedProxyId = '0x94cfcdd7';
+            expect(proxyId).to.equal(expectedProxyId);
+        });
+        describe('transferFrom', () => {
+            it('should transfer a single ERC20 token', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const amounts = [erc20Amount];
+                const nestedAssetData = [erc20AssetData];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalAmount = inputAmount.times(erc20Amount);
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalAmount),
+                );
+            });
+            it('should dispatch an ERC20 transfer when input amount is 0', async () => {
+                const inputAmount = constants.ZERO_AMOUNT;
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const amounts = [erc20Amount];
+                const nestedAssetData = [erc20AssetData];
+                const assetData = assetDataInterface.MultiAsset.getABIEncodedTransactionData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const logDecoder = new LogDecoder(web3Wrapper, { ...artifacts, ...erc20Artifacts });
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                );
+                expect(tx.logs.length).to.be.equal(1);
+                const log = tx.logs[0] as LogWithDecodedArgs<DummyERC20TokenTransferEventArgs>;
+                const transferEventName = 'Transfer';
+                expect(log.event).to.equal(transferEventName);
+                expect(log.args._value).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances).to.deep.equal(erc20Balances);
+            });
+            it('should successfully transfer multiple of the same ERC20 token', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount1 = new BigNumber(10);
+                const erc20Amount2 = new BigNumber(20);
+                const erc20AssetData1 = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc20AssetData2 = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const amounts = [erc20Amount1, erc20Amount2];
+                const nestedAssetData = [erc20AssetData1, erc20AssetData2];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalAmount = inputAmount.times(erc20Amount1).plus(inputAmount.times(erc20Amount2));
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalAmount),
+                );
+            });
+            it('should successfully transfer multiple different ERC20 tokens', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount1 = new BigNumber(10);
+                const erc20Amount2 = new BigNumber(20);
+                const erc20AssetData1 = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc20AssetData2 = assetDataUtils.encodeERC20AssetData(erc20TokenB.address);
+                const amounts = [erc20Amount1, erc20Amount2];
+                const nestedAssetData = [erc20AssetData1, erc20AssetData2];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalErc20AAmount = inputAmount.times(erc20Amount1);
+                const totalErc20BAmount = inputAmount.times(erc20Amount2);
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalErc20AAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalErc20AAmount),
+                );
+                expect(newBalances[fromAddress][erc20TokenB.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenB.address].minus(totalErc20BAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenB.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenB.address].plus(totalErc20BAmount),
+                );
+            });
+            it('should transfer a single ERC721 token', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc721Amount = new BigNumber(1);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const amounts = [erc721Amount];
+                const nestedAssetData = [erc721AssetData];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newOwnerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwnerFromAsset).to.be.equal(toAddress);
+            });
+            it('should successfully transfer multiple of the same ERC721 token', async () => {
+                const erc721Balances = await erc721Wrapper.getBalancesAsync();
+                const erc721AFromTokenId2 = erc721Balances[fromAddress][erc721TokenA.address][1];
+                const erc721AssetData1 = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const erc721AssetData2 = assetDataUtils.encodeERC721AssetData(
+                    erc721TokenA.address,
+                    erc721AFromTokenId2,
+                );
+                const inputAmount = new BigNumber(1);
+                const erc721Amount = new BigNumber(1);
+                const amounts = [erc721Amount, erc721Amount];
+                const nestedAssetData = [erc721AssetData1, erc721AssetData2];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const ownerFromAsset1 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset1).to.be.equal(fromAddress);
+                const ownerFromAsset2 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId2);
+                expect(ownerFromAsset2).to.be.equal(fromAddress);
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                        gas: constants.MAX_TRANSFER_FROM_GAS,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newOwnerFromAsset1 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                const newOwnerFromAsset2 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId2);
+                expect(newOwnerFromAsset1).to.be.equal(toAddress);
+                expect(newOwnerFromAsset2).to.be.equal(toAddress);
+            });
+            it('should successfully transfer multiple different ERC721 tokens', async () => {
+                const erc721AssetData1 = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const erc721AssetData2 = assetDataUtils.encodeERC721AssetData(erc721TokenB.address, erc721BFromTokenId);
+                const inputAmount = new BigNumber(1);
+                const erc721Amount = new BigNumber(1);
+                const amounts = [erc721Amount, erc721Amount];
+                const nestedAssetData = [erc721AssetData1, erc721AssetData2];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const ownerFromAsset1 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset1).to.be.equal(fromAddress);
+                const ownerFromAsset2 = await erc721TokenB.ownerOf.callAsync(erc721BFromTokenId);
+                expect(ownerFromAsset2).to.be.equal(fromAddress);
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                        gas: constants.MAX_TRANSFER_FROM_GAS,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newOwnerFromAsset1 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                const newOwnerFromAsset2 = await erc721TokenB.ownerOf.callAsync(erc721BFromTokenId);
+                expect(newOwnerFromAsset1).to.be.equal(toAddress);
+                expect(newOwnerFromAsset2).to.be.equal(toAddress);
+            });
+            it('should successfully transfer a combination of ERC20 and ERC721 tokens', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc721Amount = new BigNumber(1);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const amounts = [erc20Amount, erc721Amount];
+                const nestedAssetData = [erc20AssetData, erc721AssetData];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalAmount = inputAmount.times(erc20Amount);
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalAmount),
+                );
+                const newOwnerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwnerFromAsset).to.be.equal(toAddress);
+            });
+            it('should successfully transfer tokens and ignore extra assetData', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc721Amount = new BigNumber(1);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const amounts = [erc20Amount, erc721Amount];
+                const nestedAssetData = [erc20AssetData, erc721AssetData];
+                const extraData = '0102030405060708';
+                const assetData = `${assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData)}${extraData}`;
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const ownerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset).to.be.equal(fromAddress);
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalAmount = inputAmount.times(erc20Amount);
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalAmount),
+                );
+                const newOwnerFromAsset = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(newOwnerFromAsset).to.be.equal(toAddress);
+            });
+            it('should successfully transfer correct amounts when the `amount` > 1', async () => {
+                const inputAmount = new BigNumber(100);
+                const erc20Amount1 = new BigNumber(10);
+                const erc20Amount2 = new BigNumber(20);
+                const erc20AssetData1 = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc20AssetData2 = assetDataUtils.encodeERC20AssetData(erc20TokenB.address);
+                const amounts = [erc20Amount1, erc20Amount2];
+                const nestedAssetData = [erc20AssetData1, erc20AssetData2];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalErc20AAmount = inputAmount.times(erc20Amount1);
+                const totalErc20BAmount = inputAmount.times(erc20Amount2);
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalErc20AAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalErc20AAmount),
+                );
+                expect(newBalances[fromAddress][erc20TokenB.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenB.address].minus(totalErc20BAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenB.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenB.address].plus(totalErc20BAmount),
+                );
+            });
+            it('should successfully transfer a large amount of tokens', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount1 = new BigNumber(10);
+                const erc20Amount2 = new BigNumber(20);
+                const erc20AssetData1 = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc20AssetData2 = assetDataUtils.encodeERC20AssetData(erc20TokenB.address);
+                const erc721Amount = new BigNumber(1);
+                const erc721Balances = await erc721Wrapper.getBalancesAsync();
+                const erc721AFromTokenId2 = erc721Balances[fromAddress][erc721TokenA.address][1];
+                const erc721BFromTokenId2 = erc721Balances[fromAddress][erc721TokenB.address][1];
+                const erc721AssetData1 = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const erc721AssetData2 = assetDataUtils.encodeERC721AssetData(
+                    erc721TokenA.address,
+                    erc721AFromTokenId2,
+                );
+                const erc721AssetData3 = assetDataUtils.encodeERC721AssetData(erc721TokenB.address, erc721BFromTokenId);
+                const erc721AssetData4 = assetDataUtils.encodeERC721AssetData(
+                    erc721TokenB.address,
+                    erc721BFromTokenId2,
+                );
+                const amounts = [erc721Amount, erc20Amount1, erc721Amount, erc20Amount2, erc721Amount, erc721Amount];
+                const nestedAssetData = [
+                    erc721AssetData1,
+                    erc20AssetData1,
+                    erc721AssetData2,
+                    erc20AssetData2,
+                    erc721AssetData3,
+                    erc721AssetData4,
+                ];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const ownerFromAsset1 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                expect(ownerFromAsset1).to.be.equal(fromAddress);
+                const ownerFromAsset2 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId2);
+                expect(ownerFromAsset2).to.be.equal(fromAddress);
+                const ownerFromAsset3 = await erc721TokenB.ownerOf.callAsync(erc721BFromTokenId);
+                expect(ownerFromAsset3).to.be.equal(fromAddress);
+                const ownerFromAsset4 = await erc721TokenB.ownerOf.callAsync(erc721BFromTokenId2);
+                expect(ownerFromAsset4).to.be.equal(fromAddress);
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                        gas: constants.MAX_EXECUTE_TRANSACTION_GAS,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const newOwnerFromAsset1 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId);
+                const newOwnerFromAsset2 = await erc721TokenA.ownerOf.callAsync(erc721AFromTokenId2);
+                const newOwnerFromAsset3 = await erc721TokenB.ownerOf.callAsync(erc721BFromTokenId);
+                const newOwnerFromAsset4 = await erc721TokenB.ownerOf.callAsync(erc721BFromTokenId2);
+                expect(newOwnerFromAsset1).to.be.equal(toAddress);
+                expect(newOwnerFromAsset2).to.be.equal(toAddress);
+                expect(newOwnerFromAsset3).to.be.equal(toAddress);
+                expect(newOwnerFromAsset4).to.be.equal(toAddress);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                const totalErc20AAmount = inputAmount.times(erc20Amount1);
+                const totalErc20BAmount = inputAmount.times(erc20Amount2);
+                expect(newBalances[fromAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenA.address].minus(totalErc20AAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenA.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenA.address].plus(totalErc20AAmount),
+                );
+                expect(newBalances[fromAddress][erc20TokenB.address]).to.be.bignumber.equal(
+                    erc20Balances[fromAddress][erc20TokenB.address].minus(totalErc20BAmount),
+                );
+                expect(newBalances[toAddress][erc20TokenB.address]).to.be.bignumber.equal(
+                    erc20Balances[toAddress][erc20TokenB.address].plus(totalErc20BAmount),
+                );
+            });
+            it('should revert if a single transfer fails', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                // 2 is an invalid erc721 amount
+                const erc721Amount = new BigNumber(2);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const amounts = [erc20Amount, erc721Amount];
+                const nestedAssetData = [erc20AssetData, erc721AssetData];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.InvalidAmount,
+                );
+            });
+            it('should revert if an AssetProxy is not registered', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc721Amount = new BigNumber(1);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const invalidProxyId = '0x12345678';
+                const invalidErc721AssetData = `${invalidProxyId}${erc721AssetData.slice(10)}`;
+                const amounts = [erc20Amount, erc721Amount];
+                const nestedAssetData = [erc20AssetData, invalidErc721AssetData];
+                // HACK: This is used to get around validation built into assetDataUtils
+                const assetData = assetDataInterface.MultiAsset.getABIEncodedTransactionData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.AssetProxyDoesNotExist,
+                );
+            });
+            it('should revert if the length of `amounts` does not match the length of `nestedAssetData`', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const amounts = [erc20Amount];
+                const nestedAssetData = [erc20AssetData, erc721AssetData];
+                // HACK: This is used to get around validation built into assetDataUtils
+                const assetData = assetDataInterface.MultiAsset.getABIEncodedTransactionData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.LengthMismatch,
+                );
+            });
+            it('should revert if amounts multiplication results in an overflow', async () => {
+                const inputAmount = new BigNumber(2).pow(128);
+                const erc20Amount = new BigNumber(2).pow(128);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const amounts = [erc20Amount];
+                const nestedAssetData = [erc20AssetData];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.Uint256Overflow,
+                );
+            });
+            it('should revert if an element of `nestedAssetData` is < 4 bytes long', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc721Amount = new BigNumber(1);
+                const erc721AssetData = '0x123456';
+                const amounts = [erc20Amount, erc721Amount];
+                const nestedAssetData = [erc20AssetData, erc721AssetData];
+                // HACK: This is used to get around validation built into assetDataUtils
+                const assetData = assetDataInterface.MultiAsset.getABIEncodedTransactionData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                    RevertReason.LengthGreaterThan3Required,
+                );
+            });
+            it('should revert if caller is not authorized', async () => {
+                const inputAmount = new BigNumber(1);
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const erc721Amount = new BigNumber(1);
+                const erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721TokenA.address, erc721AFromTokenId);
+                const amounts = [erc20Amount, erc721Amount];
+                const nestedAssetData = [erc20AssetData, erc721AssetData];
+                const assetData = assetDataUtils.encodeMultiAssetData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                await expectTransactionFailedAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: notAuthorized,
+                    }),
+                    RevertReason.SenderNotAuthorized,
+                );
+            });
+        });
+    });
+});
+// tslint:enable:no-unnecessary-type-assertion
+// tslint:disable:max-file-line-count
diff --git a/contracts/asset-proxy/test/utils/erc20_wrapper.ts b/contracts/asset-proxy/test/utils/erc20_wrapper.ts
new file mode 100644
index 000000000..12cd06ece
--- /dev/null
+++ b/contracts/asset-proxy/test/utils/erc20_wrapper.ts
@@ -0,0 +1,179 @@
+import { artifacts as tokensArtifacts, DummyERC20TokenContract } from '@0x/contracts-erc20';
+import { constants, ERC20BalancesByOwner, txDefaults } from '@0x/contracts-test-utils';
+import { assetDataUtils } from '@0x/order-utils';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import { Provider } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { ERC20ProxyContract } from '../../generated-wrappers/erc20_proxy';
+import { artifacts } from '../../src/artifacts';
+
+export class ERC20Wrapper {
+    private readonly _tokenOwnerAddresses: string[];
+    private readonly _contractOwnerAddress: string;
+    private readonly _web3Wrapper: Web3Wrapper;
+    private readonly _provider: Provider;
+    private readonly _dummyTokenContracts: DummyERC20TokenContract[];
+    private _proxyContract?: ERC20ProxyContract;
+    private _proxyIdIfExists?: string;
+    /**
+     * Instanitates an ERC20Wrapper
+     * @param provider Web3 provider to use for all JSON RPC requests
+     * @param tokenOwnerAddresses Addresses that we want to endow as owners for dummy ERC20 tokens
+     * @param contractOwnerAddress Desired owner of the contract
+     * Instance of ERC20Wrapper
+     */
+    constructor(provider: Provider, tokenOwnerAddresses: string[], contractOwnerAddress: string) {
+        this._dummyTokenContracts = [];
+        this._web3Wrapper = new Web3Wrapper(provider);
+        this._provider = provider;
+        this._tokenOwnerAddresses = tokenOwnerAddresses;
+        this._contractOwnerAddress = contractOwnerAddress;
+    }
+    public async deployDummyTokensAsync(
+        numberToDeploy: number,
+        decimals: BigNumber,
+    ): Promise<DummyERC20TokenContract[]> {
+        for (let i = 0; i < numberToDeploy; i++) {
+            this._dummyTokenContracts.push(
+                await DummyERC20TokenContract.deployFrom0xArtifactAsync(
+                    tokensArtifacts.DummyERC20Token,
+                    this._provider,
+                    txDefaults,
+                    constants.DUMMY_TOKEN_NAME,
+                    constants.DUMMY_TOKEN_SYMBOL,
+                    decimals,
+                    constants.DUMMY_TOKEN_TOTAL_SUPPLY,
+                ),
+            );
+        }
+        return this._dummyTokenContracts;
+    }
+    public async deployProxyAsync(): Promise<ERC20ProxyContract> {
+        this._proxyContract = await ERC20ProxyContract.deployFrom0xArtifactAsync(
+            artifacts.ERC20Proxy,
+            this._provider,
+            txDefaults,
+        );
+        this._proxyIdIfExists = await this._proxyContract.getProxyId.callAsync();
+        return this._proxyContract;
+    }
+    public getProxyId(): string {
+        this._validateProxyContractExistsOrThrow();
+        return this._proxyIdIfExists as string;
+    }
+    public async setBalancesAndAllowancesAsync(): Promise<void> {
+        this._validateDummyTokenContractsExistOrThrow();
+        this._validateProxyContractExistsOrThrow();
+        for (const dummyTokenContract of this._dummyTokenContracts) {
+            for (const tokenOwnerAddress of this._tokenOwnerAddresses) {
+                await this._web3Wrapper.awaitTransactionSuccessAsync(
+                    await dummyTokenContract.setBalance.sendTransactionAsync(
+                        tokenOwnerAddress,
+                        constants.INITIAL_ERC20_BALANCE,
+                        { from: this._contractOwnerAddress },
+                    ),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                await this._web3Wrapper.awaitTransactionSuccessAsync(
+                    await dummyTokenContract.approve.sendTransactionAsync(
+                        (this._proxyContract as ERC20ProxyContract).address,
+                        constants.INITIAL_ERC20_ALLOWANCE,
+                        { from: tokenOwnerAddress },
+                    ),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+            }
+        }
+    }
+    public async getBalanceAsync(userAddress: string, assetData: string): Promise<BigNumber> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        const balance = new BigNumber(await tokenContract.balanceOf.callAsync(userAddress));
+        return balance;
+    }
+    public async setBalanceAsync(userAddress: string, assetData: string, amount: BigNumber): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.setBalance.sendTransactionAsync(userAddress, amount, {
+                from: this._contractOwnerAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async getProxyAllowanceAsync(userAddress: string, assetData: string): Promise<BigNumber> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        const proxyAddress = (this._proxyContract as ERC20ProxyContract).address;
+        const allowance = new BigNumber(await tokenContract.allowance.callAsync(userAddress, proxyAddress));
+        return allowance;
+    }
+    public async setAllowanceAsync(userAddress: string, assetData: string, amount: BigNumber): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        const proxyAddress = (this._proxyContract as ERC20ProxyContract).address;
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.approve.sendTransactionAsync(proxyAddress, amount, {
+                from: userAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async getBalancesAsync(): Promise<ERC20BalancesByOwner> {
+        this._validateDummyTokenContractsExistOrThrow();
+        const balancesByOwner: ERC20BalancesByOwner = {};
+        const balances: BigNumber[] = [];
+        const balanceInfo: Array<{ tokenOwnerAddress: string; tokenAddress: string }> = [];
+        for (const dummyTokenContract of this._dummyTokenContracts) {
+            for (const tokenOwnerAddress of this._tokenOwnerAddresses) {
+                balances.push(await dummyTokenContract.balanceOf.callAsync(tokenOwnerAddress));
+                balanceInfo.push({
+                    tokenOwnerAddress,
+                    tokenAddress: dummyTokenContract.address,
+                });
+            }
+        }
+        _.forEach(balances, (balance, balanceIndex) => {
+            const tokenAddress = balanceInfo[balanceIndex].tokenAddress;
+            const tokenOwnerAddress = balanceInfo[balanceIndex].tokenOwnerAddress;
+            if (_.isUndefined(balancesByOwner[tokenOwnerAddress])) {
+                balancesByOwner[tokenOwnerAddress] = {};
+            }
+            const wrappedBalance = new BigNumber(balance);
+            balancesByOwner[tokenOwnerAddress][tokenAddress] = wrappedBalance;
+        });
+        return balancesByOwner;
+    }
+    public addDummyTokenContract(dummy: DummyERC20TokenContract): void {
+        if (!_.isUndefined(this._dummyTokenContracts)) {
+            this._dummyTokenContracts.push(dummy);
+        }
+    }
+    public addTokenOwnerAddress(address: string): void {
+        this._tokenOwnerAddresses.push(address);
+    }
+    public getTokenOwnerAddresses(): string[] {
+        return this._tokenOwnerAddresses;
+    }
+    public getTokenAddresses(): string[] {
+        const tokenAddresses = _.map(this._dummyTokenContracts, dummyTokenContract => dummyTokenContract.address);
+        return tokenAddresses;
+    }
+    private _getTokenContractFromAssetData(assetData: string): DummyERC20TokenContract {
+        const erc20ProxyData = assetDataUtils.decodeERC20AssetData(assetData);
+        const tokenAddress = erc20ProxyData.tokenAddress;
+        const tokenContractIfExists = _.find(this._dummyTokenContracts, c => c.address === tokenAddress);
+        if (_.isUndefined(tokenContractIfExists)) {
+            throw new Error(`Token: ${tokenAddress} was not deployed through ERC20Wrapper`);
+        }
+        return tokenContractIfExists;
+    }
+    private _validateDummyTokenContractsExistOrThrow(): void {
+        if (_.isUndefined(this._dummyTokenContracts)) {
+            throw new Error('Dummy ERC20 tokens not yet deployed, please call "deployDummyTokensAsync"');
+        }
+    }
+    private _validateProxyContractExistsOrThrow(): void {
+        if (_.isUndefined(this._proxyContract)) {
+            throw new Error('ERC20 proxy contract not yet deployed, please call "deployProxyAsync"');
+        }
+    }
+}
diff --git a/contracts/asset-proxy/test/utils/erc721_wrapper.ts b/contracts/asset-proxy/test/utils/erc721_wrapper.ts
new file mode 100644
index 000000000..fc43d8c52
--- /dev/null
+++ b/contracts/asset-proxy/test/utils/erc721_wrapper.ts
@@ -0,0 +1,236 @@
+import { artifacts as tokensArtifacts, DummyERC721TokenContract } from '@0x/contracts-erc721';
+import { constants, ERC721TokenIdsByOwner, txDefaults } from '@0x/contracts-test-utils';
+import { generatePseudoRandomSalt } from '@0x/order-utils';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import { Provider } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { ERC721ProxyContract } from '../../generated-wrappers/erc721_proxy';
+import { artifacts } from '../../src/artifacts';
+
+export class ERC721Wrapper {
+    private readonly _tokenOwnerAddresses: string[];
+    private readonly _contractOwnerAddress: string;
+    private readonly _web3Wrapper: Web3Wrapper;
+    private readonly _provider: Provider;
+    private readonly _dummyTokenContracts: DummyERC721TokenContract[];
+    private _proxyContract?: ERC721ProxyContract;
+    private _proxyIdIfExists?: string;
+    private _initialTokenIdsByOwner: ERC721TokenIdsByOwner = {};
+    constructor(provider: Provider, tokenOwnerAddresses: string[], contractOwnerAddress: string) {
+        this._web3Wrapper = new Web3Wrapper(provider);
+        this._provider = provider;
+        this._dummyTokenContracts = [];
+        this._tokenOwnerAddresses = tokenOwnerAddresses;
+        this._contractOwnerAddress = contractOwnerAddress;
+    }
+    public async deployDummyTokensAsync(): Promise<DummyERC721TokenContract[]> {
+        // tslint:disable-next-line:no-unused-variable
+        for (const i of _.times(constants.NUM_DUMMY_ERC721_TO_DEPLOY)) {
+            this._dummyTokenContracts.push(
+                await DummyERC721TokenContract.deployFrom0xArtifactAsync(
+                    tokensArtifacts.DummyERC721Token,
+                    this._provider,
+                    txDefaults,
+                    constants.DUMMY_TOKEN_NAME,
+                    constants.DUMMY_TOKEN_SYMBOL,
+                ),
+            );
+        }
+        return this._dummyTokenContracts;
+    }
+    public async deployProxyAsync(): Promise<ERC721ProxyContract> {
+        this._proxyContract = await ERC721ProxyContract.deployFrom0xArtifactAsync(
+            artifacts.ERC721Proxy,
+            this._provider,
+            txDefaults,
+        );
+        this._proxyIdIfExists = await this._proxyContract.getProxyId.callAsync();
+        return this._proxyContract;
+    }
+    public getProxyId(): string {
+        this._validateProxyContractExistsOrThrow();
+        return this._proxyIdIfExists as string;
+    }
+    public async setBalancesAndAllowancesAsync(): Promise<void> {
+        this._validateDummyTokenContractsExistOrThrow();
+        this._validateProxyContractExistsOrThrow();
+        this._initialTokenIdsByOwner = {};
+        for (const dummyTokenContract of this._dummyTokenContracts) {
+            for (const tokenOwnerAddress of this._tokenOwnerAddresses) {
+                // tslint:disable-next-line:no-unused-variable
+                for (const i of _.times(constants.NUM_ERC721_TOKENS_TO_MINT)) {
+                    const tokenId = generatePseudoRandomSalt();
+                    await this.mintAsync(dummyTokenContract.address, tokenId, tokenOwnerAddress);
+                    if (_.isUndefined(this._initialTokenIdsByOwner[tokenOwnerAddress])) {
+                        this._initialTokenIdsByOwner[tokenOwnerAddress] = {
+                            [dummyTokenContract.address]: [],
+                        };
+                    }
+                    if (_.isUndefined(this._initialTokenIdsByOwner[tokenOwnerAddress][dummyTokenContract.address])) {
+                        this._initialTokenIdsByOwner[tokenOwnerAddress][dummyTokenContract.address] = [];
+                    }
+                    this._initialTokenIdsByOwner[tokenOwnerAddress][dummyTokenContract.address].push(tokenId);
+
+                    await this.approveProxyAsync(dummyTokenContract.address, tokenId);
+                }
+            }
+        }
+    }
+    public async doesTokenExistAsync(tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const owner = await tokenContract.ownerOf.callAsync(tokenId);
+        const doesExist = owner !== constants.NULL_ADDRESS;
+        return doesExist;
+    }
+    public async approveProxyAsync(tokenAddress: string, tokenId: BigNumber): Promise<void> {
+        const proxyAddress = (this._proxyContract as ERC721ProxyContract).address;
+        await this.approveAsync(proxyAddress, tokenAddress, tokenId);
+    }
+    public async approveProxyForAllAsync(tokenAddress: string, tokenId: BigNumber, isApproved: boolean): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const tokenOwner = await this.ownerOfAsync(tokenAddress, tokenId);
+        const proxyAddress = (this._proxyContract as ERC721ProxyContract).address;
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.setApprovalForAll.sendTransactionAsync(proxyAddress, isApproved, {
+                from: tokenOwner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async approveAsync(to: string, tokenAddress: string, tokenId: BigNumber): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const tokenOwner = await this.ownerOfAsync(tokenAddress, tokenId);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.approve.sendTransactionAsync(to, tokenId, {
+                from: tokenOwner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async transferFromAsync(
+        tokenAddress: string,
+        tokenId: BigNumber,
+        currentOwner: string,
+        userAddress: string,
+    ): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.transferFrom.sendTransactionAsync(currentOwner, userAddress, tokenId, {
+                from: currentOwner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async mintAsync(tokenAddress: string, tokenId: BigNumber, userAddress: string): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.mint.sendTransactionAsync(userAddress, tokenId, {
+                from: this._contractOwnerAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async burnAsync(tokenAddress: string, tokenId: BigNumber, owner: string): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.burn.sendTransactionAsync(owner, tokenId, {
+                from: this._contractOwnerAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async ownerOfAsync(tokenAddress: string, tokenId: BigNumber): Promise<string> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const owner = await tokenContract.ownerOf.callAsync(tokenId);
+        return owner;
+    }
+    public async isOwnerAsync(userAddress: string, tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const tokenOwner = await tokenContract.ownerOf.callAsync(tokenId);
+        const isOwner = tokenOwner === userAddress;
+        return isOwner;
+    }
+    public async isProxyApprovedForAllAsync(userAddress: string, tokenAddress: string): Promise<boolean> {
+        this._validateProxyContractExistsOrThrow();
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const operator = (this._proxyContract as ERC721ProxyContract).address;
+        const didApproveAll = await tokenContract.isApprovedForAll.callAsync(userAddress, operator);
+        return didApproveAll;
+    }
+    public async isProxyApprovedAsync(tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
+        this._validateProxyContractExistsOrThrow();
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const approvedAddress = await tokenContract.getApproved.callAsync(tokenId);
+        const proxyAddress = (this._proxyContract as ERC721ProxyContract).address;
+        const isProxyAnApprovedOperator = approvedAddress === proxyAddress;
+        return isProxyAnApprovedOperator;
+    }
+    public async getBalancesAsync(): Promise<ERC721TokenIdsByOwner> {
+        this._validateDummyTokenContractsExistOrThrow();
+        this._validateBalancesAndAllowancesSetOrThrow();
+        const tokenIdsByOwner: ERC721TokenIdsByOwner = {};
+        const tokenOwnerAddresses: string[] = [];
+        const tokenInfo: Array<{ tokenId: BigNumber; tokenAddress: string }> = [];
+        for (const dummyTokenContract of this._dummyTokenContracts) {
+            for (const tokenOwnerAddress of this._tokenOwnerAddresses) {
+                const initialTokenOwnerIds = this._initialTokenIdsByOwner[tokenOwnerAddress][
+                    dummyTokenContract.address
+                ];
+                for (const tokenId of initialTokenOwnerIds) {
+                    tokenOwnerAddresses.push(await dummyTokenContract.ownerOf.callAsync(tokenId));
+                    tokenInfo.push({
+                        tokenId,
+                        tokenAddress: dummyTokenContract.address,
+                    });
+                }
+            }
+        }
+        _.forEach(tokenOwnerAddresses, (tokenOwnerAddress, ownerIndex) => {
+            const tokenAddress = tokenInfo[ownerIndex].tokenAddress;
+            const tokenId = tokenInfo[ownerIndex].tokenId;
+            if (_.isUndefined(tokenIdsByOwner[tokenOwnerAddress])) {
+                tokenIdsByOwner[tokenOwnerAddress] = {
+                    [tokenAddress]: [],
+                };
+            }
+            if (_.isUndefined(tokenIdsByOwner[tokenOwnerAddress][tokenAddress])) {
+                tokenIdsByOwner[tokenOwnerAddress][tokenAddress] = [];
+            }
+            tokenIdsByOwner[tokenOwnerAddress][tokenAddress].push(tokenId);
+        });
+        return tokenIdsByOwner;
+    }
+    public getTokenOwnerAddresses(): string[] {
+        return this._tokenOwnerAddresses;
+    }
+    public getTokenAddresses(): string[] {
+        const tokenAddresses = _.map(this._dummyTokenContracts, dummyTokenContract => dummyTokenContract.address);
+        return tokenAddresses;
+    }
+    private _getTokenContractFromAssetData(tokenAddress: string): DummyERC721TokenContract {
+        const tokenContractIfExists = _.find(this._dummyTokenContracts, c => c.address === tokenAddress);
+        if (_.isUndefined(tokenContractIfExists)) {
+            throw new Error(`Token: ${tokenAddress} was not deployed through ERC20Wrapper`);
+        }
+        return tokenContractIfExists;
+    }
+    private _validateDummyTokenContractsExistOrThrow(): void {
+        if (_.isUndefined(this._dummyTokenContracts)) {
+            throw new Error('Dummy ERC721 tokens not yet deployed, please call "deployDummyTokensAsync"');
+        }
+    }
+    private _validateProxyContractExistsOrThrow(): void {
+        if (_.isUndefined(this._proxyContract)) {
+            throw new Error('ERC721 proxy contract not yet deployed, please call "deployProxyAsync"');
+        }
+    }
+    private _validateBalancesAndAllowancesSetOrThrow(): void {
+        if (_.keys(this._initialTokenIdsByOwner).length === 0) {
+            throw new Error(
+                'Dummy ERC721 balances and allowances not yet set, please call "setBalancesAndAllowancesAsync"',
+            );
+        }
+    }
+}
diff --git a/contracts/asset-proxy/test/utils/index.ts b/contracts/asset-proxy/test/utils/index.ts
new file mode 100644
index 000000000..b11f6a45d
--- /dev/null
+++ b/contracts/asset-proxy/test/utils/index.ts
@@ -0,0 +1,2 @@
+export * from './erc20_wrapper';
+export * from './erc721_wrapper';
diff --git a/contracts/asset-proxy/tsconfig.json b/contracts/asset-proxy/tsconfig.json
new file mode 100644
index 000000000..7baa48cbe
--- /dev/null
+++ b/contracts/asset-proxy/tsconfig.json
@@ -0,0 +1,19 @@
+{
+    "extends": "../../tsconfig",
+    "compilerOptions": {
+        "outDir": "lib",
+        "rootDir": ".",
+        "resolveJsonModule": true
+    },
+    "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
+    "files": [
+        "./generated-artifacts/IAssetData.json",
+        "./generated-artifacts/IAssetProxy.json",
+        "./generated-artifacts/IAuthorizable.json",
+        "./generated-artifacts/ERC20Proxy.json",
+        "./generated-artifacts/ERC721Proxy.json",
+        "./generated-artifacts/MixinAuthorizable.json",
+        "./generated-artifacts/MultiAssetProxy.json"
+    ],
+    "exclude": ["./deploy/solc/solc_bin"]
+}
diff --git a/contracts/asset-proxy/tslint.json b/contracts/asset-proxy/tslint.json
new file mode 100644
index 000000000..1bb3ac2a2
--- /dev/null
+++ b/contracts/asset-proxy/tslint.json
@@ -0,0 +1,6 @@
+{
+    "extends": ["@0x/tslint-config"],
+    "rules": {
+        "custom-no-magic-numbers": false
+    }
+}