.

lib/server.js

@@ -170,7 +170,28 @@ CopayServer.prototype._doCreateAddress = function (pkr, index, isChange) {
 	});
 };
 
-CopayServer.prototype._verifyMessageSignature = function (copayerId, message, signature) {
+/**
+ * Verifies that a given message was actually sent by an authorized copayer.
+ * @param {Object} opts
+ * @param {string} opts.walletId - The wallet id.
+ * @param {string} opts.copayerId - The wallet id.
+ * @param {string} opts.message - The message to verify.
+ * @param {string} opts.signature - The signature of message to verify.
+ * @returns {truthy} The result of the verification.
+ */
+CopayServer.prototype.verifyMessageSignature = function (opts, cb) {
+	var self = this;
+
+	self.storage.fetchCopayer(opts.walletId, opts.copayerId, function (err, copayer) {
+		if (err) return cb(err);
+		if (!copayer) return cb('Copayer not found');
+
+		var isValid = self._doVerifyMessageSignature(copayer.xPubKey, opts.message, opts.signature);
+		return cb(null, isValid);
+	});
+};
+
+CopayServer.prototype._doVerifyMessageSignature = function (pubKey, message, signature) {
 	throw 'not implemented';
 };
 
@@ -238,25 +259,18 @@ CopayServer.prototype._doCreateTx = function (copayerId, toAddress, amount, chan
  * @param {Object} opts
  * @param {string} opts.walletId - The wallet id.
  * @param {string} opts.copayerId - The wallet id.
- * @param {truthy} opts.otToken - A one-time token used to avoid reply attacks.
  * @param {string} opts.toAddress - Destination address.
  * @param {number} opts.amount - Amount to transfer in satoshi.
  * @param {string} opts.message - A message to attach to this transaction.
- * @param {string} opts.requestSignature - Signature of the request (toAddress + amount + otToken).
  * @returns {TxProposal} Transaction proposal. 
  */
 CopayServer.prototype.createTx = function (opts, cb) {
-	// Client generates a unique token and signs toAddress + amount + token.
-	// This way we authenticate + avoid replay attacks.
 	var self = this;
 
 	self.getWallet({ id: opts.walletId }, function (err, wallet) {
 		if (err) return cb(err);
 		if (!wallet) return cb('Wallet not found');
 
-		var msg = '' + opts.toAddress + opts.amount + opts.otToken;
-		if (!self._verifyMessageSignature(opts.copayerId, msg, opts.requestSignature)) return cb('Invalid request');
-
 		self._getUtxos({ walletId: wallet.id }, function (err, utxos) {
 			if (err) return cb('Could not retrieve UTXOs');
 			
@@ -273,10 +287,49 @@ CopayServer.prototype.createTx = function (opts, cb) {
 	});
 }; 
 
+/**
+ * Sign a transaction proposal.
+ * @param {Object} opts
+ * @param {string} opts.walletId - The wallet id.
+ * @param {string} opts.copayerId - The wallet id.
+ * @param {string} opts.ntxid - The identifier of the transaction.
+ * @param {string} opts.signature - The signature of the tx for this copayer.
+ */
+CopayServer.prototype.signTx = function (opts, cb) {
+	var self = this;
+
+	self.getWallet({ id: opts.walletId }, function (err, wallet) {
+		if (err) return cb(err);
+		if (!wallet) return cb('Wallet not found');
+
+		self._getUtxos({ walletId: wallet.id }, function (err, utxos) {
+			if (err) return cb('Could not retrieve UTXOs');
+			
+			self._doCreateTx(opts.copayerId, opts.toAddress, opts.amount, opts.changeAddress, utxos, function (err, tx) {
+				if (err) return cb('Could not create transaction');
+
+				self.storage.storeTx(tx, function (err) {
+					if (err) return cb(err);
+
+					return cb(null, tx);
+				});
+			});
+		});
+	});
+}; 
+
+
+/**
+ * Retrieves all pending transaction proposals.
+ * @param {Object} opts
+ * @param {string} opts.walletId - The wallet id.
+ * @param {string} opts.copayerId - The wallet id.
+ * @returns {TxProposal[]} Transaction proposal. 
+ */
 CopayServer.prototype.getPendingTxs = function (opts, cb) {
 	var self = this;
 
-	//self.storage.get
+	throw 'not implemented';	
 };
 
 

lib/storage.js

@@ -27,6 +27,16 @@ Storage.prototype.fetchWallet = function (id, cb) {
 	});
 };
 
+Storage.prototype.fetchCopayer = function (walletId, copayerId, cb) {
+	this.db.get('wallet-' + walletId + '-copayer-' + copayerId, function (err, data) {
+		if (err) {
+			if (err.notFound) return cb();
+			return cb(err);
+		}
+		return cb(null, Copayer.fromObj(data));
+	});
+};
+
 Storage.prototype.fetchCopayers = function (walletId, cb) {
 	var copayers = [];
 	var key = 'wallet-' + walletId + '-copayer-';

test/integration.js

@@ -324,6 +324,46 @@ describe('Copay server', function() {
     });
   };
 
+  describe('#_verifyMessageSignature', function() {
+    beforeEach(function() {
+      server = new CopayServer({
+        storage: storage,
+      });
+    });
+
+    it('should successfully verify message signature', function (done) {
+      server._doVerifyMessageSignature = sinon.stub().returns(true);
+      helpers.createAndJoinWallet('123', 2, 2, function (err, wallet) {
+        var opts = {
+          walletId: '123',
+          copayerId: '1',
+          message: 'hello world',
+          signature: 'dummy',
+        };
+        server.verifyMessageSignature(opts, function (err, isValid) {
+          should.not.exist(err);
+          isValid.should.be.true;
+          done();
+        });
+      });
+    });
+
+    it('should fail to verify message signature when copayer does not exist', function (done) {
+      helpers.createAndJoinWallet('123', 2, 2, function (err, wallet) {
+        var opts = {
+          walletId: '123',
+          copayerId: '999',
+          message: 'hello world',
+          signature: 'dummy',
+        };
+        server.verifyMessageSignature(opts, function (err, isValid) {
+          err.should.exist;
+          done();
+        });
+      });
+    });
+  });
+
   describe('#createAddress', function() {
     beforeEach(function() {
       server = new CopayServer({