Move isValidSignature back from utils

1 files changed, 13 insertions, 1 deletions

diff --git a/src/0x.js.ts b/src/0x.js.ts
index f275d9fbd..8f1178b2a 100644
--- a/src/0x.js.ts
+++ b/src/0x.js.ts
@@ -40,7 +40,19 @@ export class ZeroEx {
         assert.doesConformToSchema('signature', signature, ecSignatureSchema);
         assert.isETHAddressHex('signerAddressHex', signerAddressHex);
 
-        return utils.isValidSignature(dataHex, signature, 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;
+        }
     }
     /**
      * Generates pseudo-random 256 bit salt.