Use secp256k1 c bindings to verify signatures

lib/common/utils.js

@@ -1,9 +1,10 @@
 var $ = require('preconditions').singleton();
 var _ = require('lodash');
 
-var Bitcore = require('bitcore-lib');
-var crypto = Bitcore.crypto;
-var encoding = Bitcore.encoding;
+var bitcore = require('bitcore-lib');
+var crypto = bitcore.crypto;
+var encoding = bitcore.encoding;
+var secp256k1 = require('secp256k1');
 
 var Utils = {};
 
@@ -28,28 +29,62 @@ Utils.strip = function(number) {
 
 /* TODO: It would be nice to be compatible with bitcoind signmessage. How
  * the hash is calculated there? */
-Utils.hashMessage = function(text) {
+Utils.hashMessage = function(text, noReverse) {
   $.checkArgument(text);
   var buf = new Buffer(text);
   var ret = crypto.Hash.sha256sha256(buf);
-  ret = new Bitcore.encoding.BufferReader(ret).readReverse();
+  if (!noReverse) {
+    ret = new bitcore.encoding.BufferReader(ret).readReverse();
+  }
   return ret;
 };
 
-Utils.verifyMessage = function(text, signature, pubKey) {
+Utils.verifyMessage = function(text, signature, publicKey) {
   $.checkArgument(text);
-  $.checkArgument(pubKey);
 
-  if (!signature)
+  var hash = Utils.hashMessage(text, true);
+
+  var sig = this._tryImportSignature(signature);
+  if (!sig) {
+    return false;
+  }
+
+  var publicKeyBuffer = this._tryImportPublicKey(publicKey);
+  if (!publicKeyBuffer) {
     return false;
+  }
+
+  return this._tryVerifyMessage(hash, sig, publicKeyBuffer);
+};
 
-  var pub = new Bitcore.PublicKey(pubKey);
-  var hash = Utils.hashMessage(text);
+Utils._tryImportPublicKey = function(publicKey) {
+  var publicKeyBuffer = publicKey;
+  try {
+    if (!Buffer.isBuffer(publicKey)) {
+      publicKeyBuffer = new Buffer(publicKey, 'hex');
+    }
+    return publicKeyBuffer;
+  } catch(e) {
+    return false;
+  }
+};
+
+Utils._tryImportSignature = function(signature) {
+  try {
+    var signatureBuffer = signature;
+    if (!Buffer.isBuffer(signature)) {
+      signatureBuffer = new Buffer(signature, 'hex');
+    }
+    return secp256k1.signatureImport(signatureBuffer);
+  } catch(e) {
+    return false;
+  }
+};
 
+Utils._tryVerifyMessage = function(hash, sig, publicKeyBuffer) {
   try {
-    var sig = new crypto.Signature.fromString(signature);
-    return crypto.ECDSA.verify(hash, sig, pub, 'little');
-  } catch (e) {
+    return secp256k1.verify(hash, sig, publicKeyBuffer);
+  } catch(e) {
     return false;
   }
 };

package.json

@@ -42,6 +42,7 @@
     "preconditions": "^1.0.7",
     "read": "^1.0.5",
     "request": "^2.53.0",
+    "secp256k1": "^3.1.0",
     "sjcl": "^1.0.2",
     "socket.io": "^1.3.5",
     "socket.io-client": "^1.3.5",