Add utils for hashing and signing orders, update wrappers

1 files changed, 30 insertions, 0 deletions

diff --git a/packages/contracts/src/utils/signing_utils.ts b/packages/contracts/src/utils/signing_utils.ts
new file mode 100644
index 000000000..21b69619c
--- /dev/null
+++ b/packages/contracts/src/utils/signing_utils.ts
@@ -0,0 +1,30 @@
+import * as ethUtil from 'ethereumjs-util';
+
+import { SignatureType } from './types';
+
+export const signingUtils = {
+    signMessage(message: Buffer, secretKey: Buffer, signatureType: SignatureType): Buffer {
+        if (signatureType === SignatureType.Ecrecover) {
+            const prefixedMessage = ethUtil.hashPersonalMessage(message);
+            const ecSignature = ethUtil.ecsign(prefixedMessage, secretKey);
+            const signature = Buffer.concat([
+                ethUtil.toBuffer(signatureType),
+                ethUtil.toBuffer(ecSignature.v),
+                ecSignature.r,
+                ecSignature.s,
+            ]);
+            return signature;
+        } else if (signatureType === SignatureType.EIP712) {
+            const ecSignature = ethUtil.ecsign(message, secretKey);
+            const signature = Buffer.concat([
+                ethUtil.toBuffer(signatureType),
+                ethUtil.toBuffer(ecSignature.v),
+                ecSignature.r,
+                ecSignature.s,
+            ]);
+            return signature;
+        } else {
+            throw new Error(`${signatureType} is not a valid signature type`);
+        }
+    },
+};