Switch over to Lerna + Yarn Workspaces setup for a mono-repo approach

1 files changed, 44 insertions, 0 deletions

diff --git a/packages/0x.js/src/utils/signature_utils.ts b/packages/0x.js/src/utils/signature_utils.ts
new file mode 100644
index 000000000..d066f8bf0
--- /dev/null
+++ b/packages/0x.js/src/utils/signature_utils.ts
@@ -0,0 +1,44 @@
+import * as ethUtil from 'ethereumjs-util';
+import {ECSignature} from '../types';
+
+export const signatureUtils = {
+    isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
+        const dataBuff = ethUtil.toBuffer(data);
+        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 === signerAddress;
+        } catch (err) {
+            return false;
+        }
+    },
+    parseSignatureHexAsVRS(signatureHex: string): ECSignature {
+        const signatureBuffer = ethUtil.toBuffer(signatureHex);
+        let v = signatureBuffer[0];
+        if (v < 27) {
+            v += 27;
+        }
+        const r = signatureBuffer.slice(1, 33);
+        const s = signatureBuffer.slice(33, 65);
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        return ecSignature;
+    },
+    parseSignatureHexAsRSV(signatureHex: string): ECSignature {
+        const {v, r, s} = ethUtil.fromRpcSig(signatureHex);
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        return ecSignature;
+    },
+};