3 files changed, 19 insertions, 15 deletions
diff --git a/src/0x.js.ts b/src/0x.js.ts
index 8f1178b2a..f275d9fbd 100644
--- a/src/0x.js.ts
+++ b/src/0x.js.ts
@@ -40,19 +40,7 @@ export class ZeroEx {
         assert.doesConformToSchema('signature', signature, ecSignatureSchema);
         assert.isETHAddressHex('signerAddressHex', signerAddressHex);
 
-        const dataBuff = ethUtil.toBuffer(dataHex);
-        const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff);
-        try {
-            const pubKey = ethUtil.ecrecover(
-                msgHashBuff,
-                signature.v,
-                ethUtil.toBuffer(signature.r),
-                ethUtil.toBuffer(signature.s));
-            const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
-            return retrievedAddress === signerAddressHex;
-        } catch (err) {
-            return false;
-        }
+        return utils.isValidSignature(dataHex, signature, signerAddressHex);
     }
     /**
      * Generates pseudo-random 256 bit salt.
diff --git a/src/contract_wrappers/exchange_wrapper.ts b/src/contract_wrappers/exchange_wrapper.ts
index d144d8aad..5b5d1e914 100644
--- a/src/contract_wrappers/exchange_wrapper.ts
+++ b/src/contract_wrappers/exchange_wrapper.ts
@@ -70,8 +70,8 @@ export class ExchangeWrapper extends ContractWrapper {
         await this.stopWatchingExchangeLogEventsAsync();
         delete this.exchangeContractIfExists;
     }
-    public async isValidSignatureAsync(dataHex: string, ecSignature: ECSignature,
-                                       signerAddressHex: string): Promise<boolean> {
+    private async isValidSignatureUsingContractCallAsync(dataHex: string, ecSignature: ECSignature,
+                                                         signerAddressHex: string): Promise<boolean> {
         assert.isHexString('dataHex', dataHex);
         assert.doesConformToSchema('ecSignature', ecSignature, ecSignatureSchema);
         assert.isETHAddressHex('signerAddressHex', signerAddressHex);
diff --git a/src/utils/utils.ts b/src/utils/utils.ts
index 5786bab07..ea3d8c7e1 100644
--- a/src/utils/utils.ts
+++ b/src/utils/utils.ts
@@ -4,6 +4,7 @@ import * as ethABI from 'ethereumjs-abi';
 import * as ethUtil from 'ethereumjs-util';
 import {Order, SignedOrder, SolidityTypes} from '../types';
 import * as BigNumber from 'bignumber.js';
+import {ECSignature} from '../types';
 
 export const utils = {
     /**
@@ -50,6 +51,21 @@ export const utils = {
         const hashHex = ethUtil.bufferToHex(hashBuff);
         return hashHex;
     },
+    isValidSignature(dataHex: string, signature: ECSignature, signerAddressHex: string): boolean {
+        const dataBuff = ethUtil.toBuffer(dataHex);
+        const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff);
+        try {
+            const pubKey = ethUtil.ecrecover(
+                msgHashBuff,
+                signature.v,
+                ethUtil.toBuffer(signature.r),
+                ethUtil.toBuffer(signature.s));
+            const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
+            return retrievedAddress === signerAddressHex;
+        } catch (err) {
+            return false;
+        }
+    },
     getCurrentUnixTimestamp(): BigNumber.BigNumber {
         return new BigNumber(Date.now() / 1000);
     },