Merge branch 'development' into dev-section-redesign

* development: (62 commits)
  Fix linter error
  Upgrade ethereum-types
  Lint and update deps
  Be more explicit with falsiness
  Add type to cssRuleIfExists
  Fix issue where we throw if non-numeric characters are used in input
  Upgrade to more recent types, fix yarn.lock
  [fix]: [testnet-faucet] Exit 1 on build fail
  Explains tools we want them to use
  Add note about button
  Add dev-tools-pages bundles to gitignore
  Improve README
  Fix button and center
  Increase max bundle size for instant
  Add stuff
  Initial project scaffolding
  Change tslint config to remove conflicts with prettier
  fix: [testnet-faucet] Signing of orders
  Update the CHANGELOG
  Add comments for expiryBuffer
  ...

7 files changed, 226 insertions, 218 deletions

diff --git a/packages/order-utils/src/constants.ts b/packages/order-utils/src/constants.ts
index c23578c20..7de20a696 100644
--- a/packages/order-utils/src/constants.ts
+++ b/packages/order-utils/src/constants.ts
@@ -13,4 +13,39 @@ export const constants = {
     BASE_16: 16,
     INFINITE_TIMESTAMP_SEC: new BigNumber(2524604400), // Close to infinite
     ZERO_AMOUNT: new BigNumber(0),
+    EIP712_DOMAIN_NAME: '0x Protocol',
+    EIP712_DOMAIN_VERSION: '2',
+    EIP712_DOMAIN_SCHEMA: {
+        name: 'EIP712Domain',
+        parameters: [
+            { name: 'name', type: 'string' },
+            { name: 'version', type: 'string' },
+            { name: 'verifyingContract', type: 'address' },
+        ],
+    },
+    EIP712_ORDER_SCHEMA: {
+        name: 'Order',
+        parameters: [
+            { name: 'makerAddress', type: 'address' },
+            { name: 'takerAddress', type: 'address' },
+            { name: 'feeRecipientAddress', type: 'address' },
+            { name: 'senderAddress', type: 'address' },
+            { name: 'makerAssetAmount', type: 'uint256' },
+            { name: 'takerAssetAmount', type: 'uint256' },
+            { name: 'makerFee', type: 'uint256' },
+            { name: 'takerFee', type: 'uint256' },
+            { name: 'expirationTimeSeconds', type: 'uint256' },
+            { name: 'salt', type: 'uint256' },
+            { name: 'makerAssetData', type: 'bytes' },
+            { name: 'takerAssetData', type: 'bytes' },
+        ],
+    },
+    EIP712_ZEROEX_TRANSACTION_SCHEMA: {
+        name: 'ZeroExTransaction',
+        parameters: [
+            { name: 'salt', type: 'uint256' },
+            { name: 'signerAddress', type: 'address' },
+            { name: 'data', type: 'bytes' },
+        ],
+    },
 };
diff --git a/packages/order-utils/src/eip712_utils.ts b/packages/order-utils/src/eip712_utils.ts
index b303c93dc..56f736500 100644
--- a/packages/order-utils/src/eip712_utils.ts
+++ b/packages/order-utils/src/eip712_utils.ts
@@ -1,109 +1,83 @@
-import ethUtil = require('ethereumjs-util');
+import { assert } from '@0xproject/assert';
+import { schemas } from '@0xproject/json-schemas';
+import { EIP712Object, EIP712TypedData, EIP712Types, Order, ZeroExTransaction } from '@0xproject/types';
 import * as _ from 'lodash';
 
-import { crypto } from './crypto';
-import { EIP712Schema, EIP712Types } from './types';
-
-const EIP191_PREFIX = '\x19\x01';
-const EIP712_DOMAIN_NAME = '0x Protocol';
-const EIP712_DOMAIN_VERSION = '2';
-const EIP712_VALUE_LENGTH = 32;
-
-const EIP712_DOMAIN_SCHEMA: EIP712Schema = {
-    name: 'EIP712Domain',
-    parameters: [
-        { name: 'name', type: EIP712Types.String },
-        { name: 'version', type: EIP712Types.String },
-        { name: 'verifyingContract', type: EIP712Types.Address },
-    ],
-};
+import { constants } from './constants';
 
 export const eip712Utils = {
     /**
-     * Compiles the EIP712Schema and returns the hash of the schema.
-     * @param   schema The EIP712 schema.
-     * @return  The hash of the compiled schema
-     */
-    compileSchema(schema: EIP712Schema): Buffer {
-        const eip712Schema = eip712Utils._encodeType(schema);
-        const eip712SchemaHashBuffer = crypto.solSHA3([eip712Schema]);
-        return eip712SchemaHashBuffer;
-    },
-    /**
-     * Merges the EIP712 hash of a struct with the DomainSeparator for 0x v2.
-     * @param   hashStruct the EIP712 hash of a struct
-     * @param   contractAddress the exchange contract address
-     * @return  The hash of an EIP712 message with domain separator prefixed
-     */
-    createEIP712Message(hashStruct: Buffer, contractAddress: string): Buffer {
-        const domainSeparatorHashBuffer = eip712Utils._getDomainSeparatorHashBuffer(contractAddress);
-        const messageBuff = crypto.solSHA3([EIP191_PREFIX, domainSeparatorHashBuffer, hashStruct]);
-        return messageBuff;
-    },
-    /**
-     * Pad an address to 32 bytes
-     * @param address Address to pad
-     * @return padded address
+     * Creates a EIP712TypedData object specific to the 0x protocol for use with signTypedData.
+     * @param   primaryType The primary type found in message
+     * @param   types The additional types for the data in message
+     * @param   message The contents of the message
+     * @param   exchangeAddress The address of the exchange contract
+     * @return  A typed data object
      */
-    pad32Address(address: string): Buffer {
-        const addressBuffer = ethUtil.toBuffer(address);
-        const addressPadded = eip712Utils.pad32Buffer(addressBuffer);
-        return addressPadded;
+    createTypedData: (
+        primaryType: string,
+        types: EIP712Types,
+        message: EIP712Object,
+        exchangeAddress: string,
+    ): EIP712TypedData => {
+        assert.isETHAddressHex('exchangeAddress', exchangeAddress);
+        assert.isString('primaryType', primaryType);
+        const typedData = {
+            types: {
+                EIP712Domain: constants.EIP712_DOMAIN_SCHEMA.parameters,
+                ...types,
+            },
+            domain: {
+                name: constants.EIP712_DOMAIN_NAME,
+                version: constants.EIP712_DOMAIN_VERSION,
+                verifyingContract: exchangeAddress,
+            },
+            message,
+            primaryType,
+        };
+        assert.doesConformToSchema('typedData', typedData, schemas.eip712TypedDataSchema);
+        return typedData;
     },
     /**
-     * Pad an buffer to 32 bytes
-     * @param buffer Address to pad
-     * @return padded buffer
+     * Creates an Order EIP712TypedData object for use with signTypedData.
+     * @param   Order the order
+     * @return  A typed data object
      */
-    pad32Buffer(buffer: Buffer): Buffer {
-        const bufferPadded = ethUtil.setLengthLeft(buffer, EIP712_VALUE_LENGTH);
-        return bufferPadded;
+    createOrderTypedData: (order: Order): EIP712TypedData => {
+        assert.doesConformToSchema('order', order, schemas.orderSchema, [schemas.hexSchema]);
+        const normalizedOrder = _.mapValues(order, value => {
+            return !_.isString(value) ? value.toString() : value;
+        });
+        const typedData = eip712Utils.createTypedData(
+            constants.EIP712_ORDER_SCHEMA.name,
+            { Order: constants.EIP712_ORDER_SCHEMA.parameters },
+            normalizedOrder,
+            order.exchangeAddress,
+        );
+        return typedData;
     },
     /**
-     * Hash together a EIP712 schema with the corresponding data
-     * @param schema EIP712-compliant schema
-     * @param data Data the complies to the schema
-     * @return A buffer containing the SHA256 hash of the schema and encoded data
+     * Creates an ExecuteTransaction EIP712TypedData object for use with signTypedData and
+     * 0x Exchange executeTransaction.
+     * @param   ZeroExTransaction the 0x transaction
+     * @param   exchangeAddress The address of the exchange contract
+     * @return  A typed data object
      */
-    structHash(schema: EIP712Schema, data: { [key: string]: any }): Buffer {
-        const encodedData = eip712Utils._encodeData(schema, data);
-        const schemaHash = eip712Utils.compileSchema(schema);
-        const hashBuffer = crypto.solSHA3([schemaHash, ...encodedData]);
-        return hashBuffer;
-    },
-    _getDomainSeparatorSchemaBuffer(): Buffer {
-        return eip712Utils.compileSchema(EIP712_DOMAIN_SCHEMA);
-    },
-    _getDomainSeparatorHashBuffer(exchangeAddress: string): Buffer {
-        const domainSeparatorSchemaBuffer = eip712Utils._getDomainSeparatorSchemaBuffer();
-        const encodedData = eip712Utils._encodeData(EIP712_DOMAIN_SCHEMA, {
-            name: EIP712_DOMAIN_NAME,
-            version: EIP712_DOMAIN_VERSION,
-            verifyingContract: exchangeAddress,
+    createZeroExTransactionTypedData: (
+        zeroExTransaction: ZeroExTransaction,
+        exchangeAddress: string,
+    ): EIP712TypedData => {
+        assert.isETHAddressHex('exchangeAddress', exchangeAddress);
+        assert.doesConformToSchema('zeroExTransaction', zeroExTransaction, schemas.zeroExTransactionSchema);
+        const normalizedTransaction = _.mapValues(zeroExTransaction, value => {
+            return !_.isString(value) ? value.toString() : value;
         });
-        const domainSeparatorHashBuff2 = crypto.solSHA3([domainSeparatorSchemaBuffer, ...encodedData]);
-        return domainSeparatorHashBuff2;
-    },
-    _encodeType(schema: EIP712Schema): string {
-        const namedTypes = _.map(schema.parameters, ({ name, type }) => `${type} ${name}`);
-        const namedTypesJoined = namedTypes.join(',');
-        const encodedType = `${schema.name}(${namedTypesJoined})`;
-        return encodedType;
-    },
-    _encodeData(schema: EIP712Schema, data: { [key: string]: any }): any {
-        const encodedValues = [];
-        for (const parameter of schema.parameters) {
-            const value = data[parameter.name];
-            if (parameter.type === EIP712Types.String || parameter.type === EIP712Types.Bytes) {
-                encodedValues.push(crypto.solSHA3([ethUtil.toBuffer(value)]));
-            } else if (parameter.type === EIP712Types.Uint256) {
-                encodedValues.push(value);
-            } else if (parameter.type === EIP712Types.Address) {
-                encodedValues.push(eip712Utils.pad32Address(value));
-            } else {
-                throw new Error(`Unable to encode ${parameter.type}`);
-            }
-        }
-        return encodedValues;
+        const typedData = eip712Utils.createTypedData(
+            constants.EIP712_ZEROEX_TRANSACTION_SCHEMA.name,
+            { ZeroExTransaction: constants.EIP712_ZEROEX_TRANSACTION_SCHEMA.parameters },
+            normalizedTransaction,
+            exchangeAddress,
+        );
+        return typedData;
     },
 };
diff --git a/packages/order-utils/src/index.ts b/packages/order-utils/src/index.ts
index 1553647c6..dbb782b85 100644
--- a/packages/order-utils/src/index.ts
+++ b/packages/order-utils/src/index.ts
@@ -2,7 +2,6 @@ export { orderHashUtils } from './order_hash';
 export { signatureUtils } from './signature_utils';
 export { generatePseudoRandomSalt } from './salt';
 export { assetDataUtils } from './asset_data_utils';
-export { eip712Utils } from './eip712_utils';
 export { marketUtils } from './market_utils';
 export { rateUtils } from './rate_utils';
 export { sortingUtils } from './sorting_utils';
@@ -19,7 +18,17 @@ export { ExchangeTransferSimulator } from './exchange_transfer_simulator';
 export { BalanceAndProxyAllowanceLazyStore } from './store/balance_and_proxy_allowance_lazy_store';
 export { OrderFilledCancelledLazyStore } from './store/order_filled_cancelled_lazy_store';
 
-export { Provider, JSONRPCRequestPayload, JSONRPCErrorCallback, JSONRPCResponsePayload } from 'ethereum-types';
+export { constants } from './constants';
+export { eip712Utils } from './eip712_utils';
+
+export {
+    Provider,
+    JSONRPCRequestPayload,
+    JSONRPCErrorCallback,
+    JSONRPCResponsePayload,
+    JSONRPCResponseError,
+} from 'ethereum-types';
+
 export {
     SignedOrder,
     Order,
@@ -29,17 +38,19 @@ export {
     ERC20AssetData,
     ERC721AssetData,
     AssetProxyId,
-    SignerType,
     SignatureType,
     OrderStateValid,
     OrderStateInvalid,
     ExchangeContractErrs,
+    EIP712Parameter,
+    EIP712TypedData,
+    EIP712Types,
+    EIP712Object,
+    EIP712ObjectValue,
+    ZeroExTransaction,
 } from '@0xproject/types';
 export {
     OrderError,
-    EIP712Parameter,
-    EIP712Schema,
-    EIP712Types,
     TradeSide,
     TransferType,
     FindFeeOrdersThatCoverFeesForTargetOrdersOpts,
diff --git a/packages/order-utils/src/order_factory.ts b/packages/order-utils/src/order_factory.ts
index b1292903a..0f0cd6046 100644
--- a/packages/order-utils/src/order_factory.ts
+++ b/packages/order-utils/src/order_factory.ts
@@ -1,4 +1,4 @@
-import { Order, SignedOrder, SignerType } from '@0xproject/types';
+import { Order, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Provider } from 'ethereum-types';
 import * as _ from 'lodash';
@@ -71,12 +71,7 @@ export const orderFactory = {
             createOrderOpts,
         );
         const orderHash = orderHashUtils.getOrderHashHex(order);
-        const signature = await signatureUtils.ecSignOrderHashAsync(
-            provider,
-            orderHash,
-            makerAddress,
-            SignerType.Default,
-        );
+        const signature = await signatureUtils.ecSignHashAsync(provider, orderHash, makerAddress);
         const signedOrder: SignedOrder = _.assign(order, { signature });
         return signedOrder;
     },
diff --git a/packages/order-utils/src/order_hash.ts b/packages/order-utils/src/order_hash.ts
index 8e98f8767..b523a3523 100644
--- a/packages/order-utils/src/order_hash.ts
+++ b/packages/order-utils/src/order_hash.ts
@@ -1,31 +1,13 @@
 import { schemas, SchemaValidator } from '@0xproject/json-schemas';
 import { Order, SignedOrder } from '@0xproject/types';
+import { signTypedDataUtils } from '@0xproject/utils';
 import * as _ from 'lodash';
 
 import { assert } from './assert';
 import { eip712Utils } from './eip712_utils';
-import { EIP712Schema, EIP712Types } from './types';
 
 const INVALID_TAKER_FORMAT = 'instance.takerAddress is not of a type(s) string';
 
-const EIP712_ORDER_SCHEMA: EIP712Schema = {
-    name: 'Order',
-    parameters: [
-        { name: 'makerAddress', type: EIP712Types.Address },
-        { name: 'takerAddress', type: EIP712Types.Address },
-        { name: 'feeRecipientAddress', type: EIP712Types.Address },
-        { name: 'senderAddress', type: EIP712Types.Address },
-        { name: 'makerAssetAmount', type: EIP712Types.Uint256 },
-        { name: 'takerAssetAmount', type: EIP712Types.Uint256 },
-        { name: 'makerFee', type: EIP712Types.Uint256 },
-        { name: 'takerFee', type: EIP712Types.Uint256 },
-        { name: 'expirationTimeSeconds', type: EIP712Types.Uint256 },
-        { name: 'salt', type: EIP712Types.Uint256 },
-        { name: 'makerAssetData', type: EIP712Types.Bytes },
-        { name: 'takerAssetData', type: EIP712Types.Bytes },
-    ],
-};
-
 export const orderHashUtils = {
     /**
      * Checks if the supplied hex encoded order hash is valid.
@@ -45,7 +27,7 @@ export const orderHashUtils = {
     /**
      * Computes the orderHash for a supplied order.
      * @param   order   An object that conforms to the Order or SignedOrder interface definitions.
-     * @return  The resulting orderHash from hashing the supplied order.
+     * @return  Hex encoded string orderHash from hashing the supplied order.
      */
     getOrderHashHex(order: SignedOrder | Order): string {
         try {
@@ -64,16 +46,13 @@ export const orderHashUtils = {
         return orderHashHex;
     },
     /**
-     * Computes the orderHash for a supplied order and returns it as a Buffer
+     * Computes the orderHash for a supplied order
      * @param   order   An object that conforms to the Order or SignedOrder interface definitions.
-     * @return  The resulting orderHash from hashing the supplied order as a Buffer
+     * @return  A Buffer containing the resulting orderHash from hashing the supplied order
      */
     getOrderHashBuffer(order: SignedOrder | Order): Buffer {
-        const orderParamsHashBuff = eip712Utils.structHash(EIP712_ORDER_SCHEMA, order);
-        const orderHashBuff = eip712Utils.createEIP712Message(orderParamsHashBuff, order.exchangeAddress);
+        const typedData = eip712Utils.createOrderTypedData(order);
+        const orderHashBuff = signTypedDataUtils.generateTypedDataHash(typedData);
         return orderHashBuff;
     },
-    _getOrderSchemaBuffer(): Buffer {
-        return eip712Utils.compileSchema(EIP712_ORDER_SCHEMA);
-    },
 };
diff --git a/packages/order-utils/src/signature_utils.ts b/packages/order-utils/src/signature_utils.ts
index 3b656d3fc..372d210d0 100644
--- a/packages/order-utils/src/signature_utils.ts
+++ b/packages/order-utils/src/signature_utils.ts
@@ -1,5 +1,5 @@
 import { schemas } from '@0xproject/json-schemas';
-import { ECSignature, SignatureType, SignerType, ValidatorSignature } from '@0xproject/types';
+import { ECSignature, Order, SignatureType, SignedOrder, ValidatorSignature } from '@0xproject/types';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider } from 'ethereum-types';
 import * as ethUtil from 'ethereumjs-util';
@@ -7,9 +7,11 @@ import * as _ from 'lodash';
 
 import { artifacts } from './artifacts';
 import { assert } from './assert';
+import { eip712Utils } from './eip712_utils';
 import { ExchangeContract } from './generated_contract_wrappers/exchange';
 import { IValidatorContract } from './generated_contract_wrappers/i_validator';
 import { IWalletContract } from './generated_contract_wrappers/i_wallet';
+import { orderHashUtils } from './order_hash';
 import { OrderError } from './types';
 import { utils } from './utils';
 
@@ -49,7 +51,7 @@ export const signatureUtils = {
 
             case SignatureType.EthSign: {
                 const ecSignature = signatureUtils.parseECSignature(signature);
-                const prefixedMessageHex = signatureUtils.addSignedMessagePrefix(data, SignerType.Default);
+                const prefixedMessageHex = signatureUtils.addSignedMessagePrefix(data);
                 return signatureUtils.isValidECSignature(prefixedMessageHex, ecSignature, signerAddress);
             }
 
@@ -192,36 +194,90 @@ export const signatureUtils = {
         }
     },
     /**
-     * Signs an orderHash and returns it's elliptic curve signature and signature type.
-     * This method currently supports TestRPC, Geth and Parity above and below V1.6.6
-     * @param   orderHash       Hex encoded orderHash to sign.
+     * Signs an order and returns a SignedOrder. First `eth_signTypedData` is requested
+     * then a fallback to `eth_sign` if not available on the supplied provider.
+     * @param   order The Order to sign.
      * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
-     *          must be available via the Provider supplied to 0x.js.
-     * @param   signerType Different signers add/require different prefixes to be prepended to the message being signed.
-     *          Since we cannot know ahead of time which signer you are using, you must supply a SignerType.
-     * @return  A hex encoded string containing the Elliptic curve signature generated by signing the orderHash and the Signature Type.
+     *          must be available via the supplied Provider.
+     * @return  A SignedOrder containing the order and Elliptic curve signature with Signature Type.
      */
-    async ecSignOrderHashAsync(
-        provider: Provider,
-        orderHash: string,
-        signerAddress: string,
-        signerType: SignerType,
-    ): Promise<string> {
+    async ecSignOrderAsync(provider: Provider, order: Order, signerAddress: string): Promise<SignedOrder> {
+        assert.doesConformToSchema('order', order, schemas.orderSchema, [schemas.hexSchema]);
+        try {
+            const signedOrder = await signatureUtils.ecSignTypedDataOrderAsync(provider, order, signerAddress);
+            return signedOrder;
+        } catch (err) {
+            // HACK: We are unable to handle specific errors thrown since provider is not an object
+            //       under our control. It could be Metamask Web3, Ethers, or any general RPC provider.
+            //       We check for a user denying the signature request in a way that supports Metamask and
+            //       Coinbase Wallet. Unfortunately for signers with a different error message,
+            //       they will receive two signature requests.
+            if (err.message.includes('User denied message signature')) {
+                throw err;
+            }
+            const orderHash = orderHashUtils.getOrderHashHex(order);
+            const signatureHex = await signatureUtils.ecSignHashAsync(provider, orderHash, signerAddress);
+            const signedOrder = {
+                ...order,
+                signature: signatureHex,
+            };
+            return signedOrder;
+        }
+    },
+    /**
+     * Signs an order using `eth_signTypedData` and returns a SignedOrder.
+     * @param   order The Order to sign.
+     * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
+     *          must be available via the supplied Provider.
+     * @return  A SignedOrder containing the order and Elliptic curve signature with Signature Type.
+     */
+    async ecSignTypedDataOrderAsync(provider: Provider, order: Order, signerAddress: string): Promise<SignedOrder> {
         assert.isWeb3Provider('provider', provider);
-        assert.isHexString('orderHash', orderHash);
         assert.isETHAddressHex('signerAddress', signerAddress);
+        assert.doesConformToSchema('order', order, schemas.orderSchema, [schemas.hexSchema]);
         const web3Wrapper = new Web3Wrapper(provider);
         await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
         const normalizedSignerAddress = signerAddress.toLowerCase();
-
-        let msgHashHex = orderHash;
-        const prefixedMsgHashHex = signatureUtils.addSignedMessagePrefix(orderHash, signerType);
-        // Metamask incorrectly implements eth_sign and does not prefix the message as per the spec
-        // Source: https://github.com/MetaMask/metamask-extension/commit/a9d36860bec424dcee8db043d3e7da6a5ff5672e
-        if (signerType === SignerType.Metamask) {
-            msgHashHex = prefixedMsgHashHex;
+        const typedData = eip712Utils.createOrderTypedData(order);
+        try {
+            const signature = await web3Wrapper.signTypedDataAsync(normalizedSignerAddress, typedData);
+            const ecSignatureRSV = parseSignatureHexAsRSV(signature);
+            const signatureBuffer = Buffer.concat([
+                ethUtil.toBuffer(ecSignatureRSV.v),
+                ethUtil.toBuffer(ecSignatureRSV.r),
+                ethUtil.toBuffer(ecSignatureRSV.s),
+                ethUtil.toBuffer(SignatureType.EIP712),
+            ]);
+            const signatureHex = `0x${signatureBuffer.toString('hex')}`;
+            return {
+                ...order,
+                signature: signatureHex,
+            };
+        } catch (err) {
+            // Detect if Metamask to transition users to the MetamaskSubprovider
+            if ((provider as any).isMetaMask) {
+                throw new Error(OrderError.InvalidMetamaskSigner);
+            } else {
+                throw err;
+            }
         }
-        const signature = await web3Wrapper.signMessageAsync(normalizedSignerAddress, msgHashHex);
+    },
+    /**
+     * Signs a hash using `eth_sign` and returns its elliptic curve signature and signature type.
+     * @param   msgHash       Hex encoded message to sign.
+     * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
+     *          must be available via the supplied Provider.
+     * @return  A hex encoded string containing the Elliptic curve signature generated by signing the msgHash and the Signature Type.
+     */
+    async ecSignHashAsync(provider: Provider, msgHash: string, signerAddress: string): Promise<string> {
+        assert.isWeb3Provider('provider', provider);
+        assert.isHexString('msgHash', msgHash);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        const web3Wrapper = new Web3Wrapper(provider);
+        await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
+        const normalizedSignerAddress = signerAddress.toLowerCase();
+        const signature = await web3Wrapper.signMessageAsync(normalizedSignerAddress, msgHash);
+        const prefixedMsgHashHex = signatureUtils.addSignedMessagePrefix(msgHash);
 
         // HACK: There is no consensus on whether the signatureHex string should be formatted as
         // v + r + s OR r + s + v, and different clients (even different versions of the same client)
@@ -238,10 +294,7 @@ export const signatureUtils = {
                 normalizedSignerAddress,
             );
             if (isValidRSVSignature) {
-                const convertedSignatureHex = signatureUtils.convertECSignatureToSignatureHex(
-                    ecSignatureRSV,
-                    signerType,
-                );
+                const convertedSignatureHex = signatureUtils.convertECSignatureToSignatureHex(ecSignatureRSV);
                 return convertedSignatureHex;
             }
         }
@@ -253,41 +306,30 @@ export const signatureUtils = {
                 normalizedSignerAddress,
             );
             if (isValidVRSSignature) {
-                const convertedSignatureHex = signatureUtils.convertECSignatureToSignatureHex(
-                    ecSignatureVRS,
-                    signerType,
-                );
+                const convertedSignatureHex = signatureUtils.convertECSignatureToSignatureHex(ecSignatureVRS);
                 return convertedSignatureHex;
             }
         }
-
-        throw new Error(OrderError.InvalidSignature);
+        // Detect if Metamask to transition users to the MetamaskSubprovider
+        if ((provider as any).isMetaMask) {
+            throw new Error(OrderError.InvalidMetamaskSigner);
+        } else {
+            throw new Error(OrderError.InvalidSignature);
+        }
     },
     /**
-     * Combines ECSignature with V,R,S and the relevant signature type for use in 0x protocol
+     * Combines ECSignature with V,R,S and the EthSign signature type for use in 0x protocol
      * @param ecSignature The ECSignature of the signed data
-     * @param signerType The SignerType of the signed data
      * @return Hex encoded string of signature (v,r,s) with Signature Type
      */
-    convertECSignatureToSignatureHex(ecSignature: ECSignature, signerType: SignerType): string {
+    convertECSignatureToSignatureHex(ecSignature: ECSignature): string {
         const signatureBuffer = Buffer.concat([
             ethUtil.toBuffer(ecSignature.v),
             ethUtil.toBuffer(ecSignature.r),
             ethUtil.toBuffer(ecSignature.s),
         ]);
         const signatureHex = `0x${signatureBuffer.toString('hex')}`;
-        let signatureType;
-        switch (signerType) {
-            case SignerType.Metamask:
-            case SignerType.Ledger:
-            case SignerType.Default: {
-                signatureType = SignatureType.EthSign;
-                break;
-            }
-            default:
-                throw new Error(`Unrecognized SignerType: ${signerType}`);
-        }
-        const signatureWithType = signatureUtils.convertToSignatureWithType(signatureHex, signatureType);
+        const signatureWithType = signatureUtils.convertToSignatureWithType(signatureHex, SignatureType.EthSign);
         return signatureWithType;
     },
     /**
@@ -304,28 +346,17 @@ export const signatureUtils = {
     /**
      * Adds the relevant prefix to the message being signed.
      * @param message Message to sign
-     * @param signerType The type of message prefix to add for a given SignerType. Different signers expect
-     *                          specific message prefixes.
      * @return Prefixed message
      */
-    addSignedMessagePrefix(message: string, signerType: SignerType = SignerType.Default): string {
+    addSignedMessagePrefix(message: string): string {
         assert.isString('message', message);
-        assert.doesBelongToStringEnum('signerType', signerType, SignerType);
-        switch (signerType) {
-            case SignerType.Metamask:
-            case SignerType.Ledger:
-            case SignerType.Default: {
-                const msgBuff = ethUtil.toBuffer(message);
-                const prefixedMsgBuff = ethUtil.hashPersonalMessage(msgBuff);
-                const prefixedMsgHex = ethUtil.bufferToHex(prefixedMsgBuff);
-                return prefixedMsgHex;
-            }
-            default:
-                throw new Error(`Unrecognized SignerType: ${signerType}`);
-        }
+        const msgBuff = ethUtil.toBuffer(message);
+        const prefixedMsgBuff = ethUtil.hashPersonalMessage(msgBuff);
+        const prefixedMsgHex = ethUtil.bufferToHex(prefixedMsgBuff);
+        return prefixedMsgHex;
     },
     /**
-     * Parse a 0x protocol hex-encoded signature string into it's ECSignature components
+     * Parse a 0x protocol hex-encoded signature string into its ECSignature components
      * @param signature A hex encoded ecSignature 0x Protocol signature
      * @return An ECSignature object with r,s,v parameters
      */
diff --git a/packages/order-utils/src/types.ts b/packages/order-utils/src/types.ts
index a843efaa4..5b13dd754 100644
--- a/packages/order-utils/src/types.ts
+++ b/packages/order-utils/src/types.ts
@@ -2,6 +2,7 @@ import { BigNumber } from '@0xproject/utils';
 
 export enum OrderError {
     InvalidSignature = 'INVALID_SIGNATURE',
+    InvalidMetamaskSigner = "MetaMask provider must be wrapped in a MetamaskSubprovider (from the '@0xproject/subproviders' package) in order to work with this method.",
 }
 
 export enum TradeSide {
@@ -14,24 +15,6 @@ export enum TransferType {
     Fee = 'fee',
 }
 
-export interface EIP712Parameter {
-    name: string;
-    type: EIP712Types;
-}
-
-export interface EIP712Schema {
-    name: string;
-    parameters: EIP712Parameter[];
-}
-
-export enum EIP712Types {
-    Address = 'address',
-    Bytes = 'bytes',
-    Bytes32 = 'bytes32',
-    String = 'string',
-    Uint256 = 'uint256',
-}
-
 export interface CreateOrderOpts {
     takerAddress?: string;
     senderAddress?: string;