3 files changed, 16 insertions, 3 deletions
diff --git a/src/ts/0x.js.ts b/src/ts/0x.js.ts
index 4b9680a18..1f9ea5f9b 100644
--- a/src/ts/0x.js.ts
+++ b/src/ts/0x.js.ts
@@ -12,13 +12,14 @@ export interface ECSignature {
 }
 
 const MAX_DIGITS_IN_UNSIGNED_256_INT = 78;
+const ORDER_HASH_LENGTH = 66;
 
 export class ZeroEx {
     /**
      * Verifies that the elliptic curve signature `signature` was generated
      * by signing `data` with the private key corresponding to the `signer` address.
      */
-    public static isValidSignature(data: string, signature: ECSignature, signer: ETHAddressHex): boolean {
+    public static isValidSignature(data: HexString, signature: ECSignature, signer: ETHAddressHex): boolean {
         assert.isString('data', data);
         assert.isObject('signature', signature);
         assert.isETHAddressHex('signer', signer);
@@ -49,4 +50,9 @@ export class ZeroEx {
         const salt = randomNumber.times(factor).round();
         return salt;
     }
+    /** Checks if order hash is valid */
+    public static isValidOrderHash(orderHash: HexString): boolean {
+        assert.isHexString('orderHash', orderHash);
+        return orderHash.length === ORDER_HASH_LENGTH;
+    }
 }
diff --git a/src/ts/globals.d.ts b/src/ts/globals.d.ts
index 0f7391b39..9b81e15bd 100644
--- a/src/ts/globals.d.ts
+++ b/src/ts/globals.d.ts
@@ -1,11 +1,12 @@
 declare type ETHPublicKey = string;
 declare type ETHAddressHex = string;
+declare type HexString = string;
 declare type ETHAddressBuff = Buffer;
 
 declare module 'ethereumjs-util' {
-    const toBuffer: (data: string) => Buffer;
+    const toBuffer: (data: HexString) => Buffer;
     const hashPersonalMessage: (msg: Buffer) => Buffer;
-    const bufferToHex: (buff: Buffer) => string;
+    const bufferToHex: (buff: Buffer) => HexString;
     const ecrecover: (msgHashBuff: Buffer, v: number, r: Buffer, s: Buffer) => ETHPublicKey;
     const pubToAddress: (pubKey: ETHPublicKey) => ETHAddressBuff;
 }
diff --git a/src/ts/utils/assert.ts b/src/ts/utils/assert.ts
index a29ae922d..602361233 100644
--- a/src/ts/utils/assert.ts
+++ b/src/ts/utils/assert.ts
@@ -2,6 +2,8 @@ import * as _ from 'lodash';
 import * as BigNumber from 'bignumber.js';
 import Web3 = require('web3');
 
+const HEX_REGEX = /^0x([0-9A-F]{2})*$/i;
+
 export const assert = {
     isBigNumber(variableName: string, value: BigNumber.BigNumber) {
         const isBigNumber = _.isObject(value) && value.isBigNumber;
@@ -10,6 +12,10 @@ export const assert = {
     isString(variableName: string, value: string) {
         this.assert(_.isString(value), this.typeAssertionMessage(variableName, 'string', value));
     },
+    isHexString(variableName: string, value: string) {
+        this.assert(_.isString(value) && HEX_REGEX.test(value),
+            this.typeAssertionMessage(variableName, 'HexString', value));
+    },
     isETHAddressHex(variableName: string, value: ETHAddressHex) {
         const web3 = new Web3();
         this.assert(web3.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));