verify signed messages

...and fix bug where i (recover param) was stored incorrectly

lib/address.js

@@ -43,6 +43,8 @@ Address.prototype.fromString = function(str) {
   }
 
   this.hashbuf = buf.slice(1);
+
+  return this;
 }
 
 Address.prototype.isValid = function() {

lib/message.js

@@ -5,6 +5,7 @@ var Pubkey = require('./pubkey');
 var BufferWriter = require('./bufferwriter');
 var Hash = require('./hash');
 var Address = require('./address');
+var Signature = require('./signature');
 
 var Message = function Message(messagebuf, key, sig, address, verified) {
   if (!(this instanceof Message))
@@ -60,7 +61,6 @@ Message.prototype.verify = function() {
   ecdsa.key.pubkey = ecdsa.sig2pubkey();
 
   if (!ecdsa.verify()) {
-    console.log(ecdsa.sigError());
     this.verified = false;
     return this;
   }
@@ -75,14 +75,14 @@ Message.prototype.verify = function() {
   return this;
 };
 
-/*
 Message.verify = function(messagebuf, sigstr, address) {
   var sigbuf = new Buffer(sigstr, 'base64');
   var message = new Message();
   message.messagebuf = messagebuf;
   message.sig = Signature().fromCompressed(sigbuf);
   message.address = address;
+
+  return message.verify().verified;
 };
-*/
 
 module.exports = Message;

lib/signature.js

@@ -12,7 +12,7 @@ var Signature = function Signature(r, s, i) {
 };
 
 Signature.prototype.fromCompressed = function(buf) {
-  var i = buf.slice(0, 1)[0];
+  var i = buf.slice(0, 1)[0] - 27 - 4; //TODO: handle uncompressed pubkeys
   var b2 = buf.slice(1, 33);
   var b3 = buf.slice(33, 65);
 
@@ -26,17 +26,23 @@ Signature.prototype.fromCompressed = function(buf) {
   this.i = i;
   this.r = BN().fromBuffer(b2);
   this.s = BN().fromBuffer(b3);
+
+  return this;
 };
 
 Signature.prototype.fromDER = function(buf) {
   var obj = Signature.parseDER(buf);
   this.r = obj.r;
   this.s = obj.s;
+
+  return this;
 };
 
 Signature.prototype.fromString = function(str) {
   var buf = new Buffer(str, 'hex');
   this.fromDER(buf);
+
+  return this;
 };
 
 Signature.parseDER = function(buf) {
@@ -101,7 +107,7 @@ Signature.prototype.toCompressed = function(i) {
   if (!(i === 0 || i === 1 || i === 2 || i === 3))
     throw new Error('i must be equal to 0, 1, 2, or 3');
   
-  var b1 = new Buffer([i]);
+  var b1 = new Buffer([i + 27 + 4]); //TODO: handle uncompressed pubkeys
   var b2 = this.r.toBuffer({size: 32});
   var b3 = this.s.toBuffer({size: 32});
   return Buffer.concat([b1, b2, b3]);

test/test.message.js

@@ -58,4 +58,23 @@ describe('Message', function() {
 
   });
 
+  describe('@verify', function() {
+    var messagebuf = new Buffer('this is my message');
+    var key = Key().fromRandom();
+
+    it('should verify a signed message', function() {
+      var sigstr = Message.sign(messagebuf, key);
+      var addr = Address().fromPubkey(key.pubkey);
+      Message.verify(messagebuf, sigstr, addr).should.equal(true);
+    });
+
+    it('should verify this known good signature', function() {
+      var addrstr = '1CKTmxj6DjGrGTfbZzVxnY4Besbv8oxSZb';
+      var address = Address().fromString(addrstr);
+      var sigstr = 'IOrTlbNBI0QO990xOw4HAjnvRl/1zR+oBMS6HOjJgfJqXp/1EnFrcJly0UcNelqJNIAH4f0abxOZiSpYmenMH4M=';
+      Message.verify(messagebuf, sigstr, address);
+    });
+
+  });
+
 });

test/test.signature.js

@@ -15,7 +15,7 @@ describe('Signature', function() {
       var blank = new Buffer(32);
       blank.fill(0);
       var compressed = Buffer.concat([
-        new Buffer([0]),
+        new Buffer([0 + 27 + 4]),
         blank,
         blank
         ]);