Merge pull request #2020 from cmgustavo/feat/bitcore-lib-message-01

Feat(bitcore-lib): adds support for verifying and signing bitcoin messages

.gitignore

@@ -5,3 +5,11 @@ node_modules/
 .vscode
 .DS_Store
 *.swp
+
+# VIM ignore
+[._]*.s[a-w][a-z]
+[._]s[a-w][a-z]
+*.un~
+Session.vim
+.netrwhist
+*~

packages/bitcore-lib/lib/message.js

@@ -0,0 +1,164 @@
+'use strict';
+
+var _ = require('lodash');
+var PrivateKey = require('./privatekey');
+var PublicKey = require('./publickey');
+var Address = require('./address');
+var BufferWriter = require('./encoding/bufferwriter');
+var ECDSA = require('./crypto/ecdsa');
+var Signature = require('./crypto/signature');
+var sha256sha256 = require('./crypto/hash').sha256sha256;
+var JSUtil = require('./util/js');
+var $ = require('./util/preconditions');
+
+
+function Message(message) {
+  if (!(this instanceof Message)) {
+    return new Message(message);
+  }
+  $.checkArgument(_.isString(message), 'First argument should be a string');
+  this.message = message;
+
+  return this;
+}
+
+Message.MAGIC_BYTES = new Buffer('Bitcoin Signed Message:\n');
+
+Message.prototype.magicHash = function magicHash() {
+  var prefix1 = BufferWriter.varintBufNum(Message.MAGIC_BYTES.length);
+  var messageBuffer = new Buffer(this.message);
+  var prefix2 = BufferWriter.varintBufNum(messageBuffer.length);
+  var buf = Buffer.concat([prefix1, Message.MAGIC_BYTES, prefix2, messageBuffer]);
+  var hash = sha256sha256(buf);
+  return hash;
+};
+
+Message.prototype._sign = function _sign(privateKey) {
+  $.checkArgument(privateKey instanceof PrivateKey,
+    'First argument should be an instance of PrivateKey');
+  var hash = this.magicHash();
+  var ecdsa = new ECDSA();
+  ecdsa.hashbuf = hash;
+  ecdsa.privkey = privateKey;
+  ecdsa.pubkey = privateKey.toPublicKey();
+  ecdsa.signRandomK();
+  ecdsa.calci();
+  return ecdsa.sig;
+};
+
+/**
+ * Will sign a message with a given bitcoin private key.
+ *
+ * @param {PrivateKey} privateKey - An instance of PrivateKey
+ * @returns {String} A base64 encoded compact signature
+ */
+Message.prototype.sign = function sign(privateKey) {
+  var signature = this._sign(privateKey);
+  return signature.toCompact().toString('base64');
+};
+
+Message.prototype._verify = function _verify(publicKey, signature) {
+  $.checkArgument(publicKey instanceof PublicKey, 'First argument should be an instance of PublicKey');
+  $.checkArgument(signature instanceof Signature, 'Second argument should be an instance of Signature');
+  var hash = this.magicHash();
+  var verified = ECDSA.verify(hash, signature, publicKey);
+  if (!verified) {
+    this.error = 'The signature was invalid';
+  }
+  return verified;
+};
+
+/**
+ * Will return a boolean of the signature is valid for a given bitcoin address.
+ * If it isn't the specific reason is accessible via the "error" member.
+ *
+ * @param {Address|String} bitcoinAddress - A bitcoin address
+ * @param {String} signatureString - A base64 encoded compact signature
+ * @returns {Boolean}
+ */
+Message.prototype.verify = function verify(bitcoinAddress, signatureString) {
+  $.checkArgument(bitcoinAddress);
+  $.checkArgument(signatureString && _.isString(signatureString));
+
+  if (_.isString(bitcoinAddress)) {
+    bitcoinAddress = Address.fromString(bitcoinAddress);
+  }
+  var signature = Signature.fromCompact(new Buffer(signatureString, 'base64'));
+
+  // recover the public key
+  var ecdsa = new ECDSA();
+  ecdsa.hashbuf = this.magicHash();
+  ecdsa.sig = signature;
+  var publicKey = ecdsa.toPublicKey();
+
+  var signatureAddress = Address.fromPublicKey(publicKey, bitcoinAddress.network);
+
+  // check that the recovered address and specified address match
+  if (bitcoinAddress.toString() !== signatureAddress.toString()) {
+    this.error = 'The signature did not match the message digest';
+    return false;
+  }
+
+  return this._verify(publicKey, signature);
+};
+
+/**
+ * Instantiate a message from a message string
+ *
+ * @param {String} str - A string of the message
+ * @returns {Message} A new instance of a Message
+ */
+Message.fromString = function(str) {
+  return new Message(str);
+};
+
+/**
+ * Instantiate a message from JSON
+ *
+ * @param {String} json - An JSON string or Object with keys: message
+ * @returns {Message} A new instance of a Message
+ */
+Message.fromJSON = function fromJSON(json) {
+  if (JSUtil.isValidJSON(json)) {
+    json = JSON.parse(json);
+  }
+  return new Message(json.message);
+};
+
+/**
+ * @returns {Object} A plain object with the message information
+ */
+Message.prototype.toObject = function toObject() {
+  return {
+    message: this.message
+  };
+};
+
+/**
+ * @returns {String} A JSON representation of the message information
+ */
+Message.prototype.toJSON = function toJSON() {
+  return JSON.stringify(this.toObject());
+};
+
+/**
+ * Will return a the string representation of the message
+ *
+ * @returns {String} Message
+ */
+Message.prototype.toString = function() {
+  return this.message;
+};
+
+/**
+ * Will return a string formatted for the console
+ *
+ * @returns {String} Message
+ */
+Message.prototype.inspect = function() {
+  return '<Message: ' + this.toString() + '>';
+};
+
+module.exports = Message;
+
+var Script = require('./script');

packages/bitcore-lib/test/message.js

@@ -0,0 +1,166 @@
+'use strict';
+
+/* jshint maxstatements: 30 */
+
+var chai = require('chai');
+var should = chai.should();
+var expect = chai.expect;
+
+var bitcore = require('..');
+var Address = bitcore.Address;
+var Signature = bitcore.crypto.Signature;
+var Message = require('../lib/message');
+
+describe('Message', function() {
+
+  var address = 'n1ZCYg9YXtB5XCZazLxSmPDa8iwJRZHhGx';
+  var badAddress = 'mmRcrB5fTwgxaFJmVLNtaG8SV454y1E3kC';
+  var privateKey = bitcore.PrivateKey.fromWIF('cPBn5A4ikZvBTQ8D7NnvHZYCAxzDZ5Z2TSGW2LkyPiLxqYaJPBW4');
+  var text = 'hello, world';
+  var signatureString = 'H/DIn8uA1scAuKLlCx+/9LnAcJtwQQ0PmcPrJUq90aboLv3fH5fFvY+vmbfOSFEtGarznYli6ShPr9RXwY9UrIY=';
+
+  var badSignatureString = 'H69qZ4mbZCcvXk7CWjptD5ypnYVLvQ3eMXLM8+1gX21SLH/GaFnAjQrDn37+TDw79i9zHhbiMMwhtvTwnPigZ6k=';
+
+  var signature = Signature.fromCompact(new Buffer(signatureString, 'base64'));
+  var badSignature = Signature.fromCompact(new Buffer(badSignatureString, 'base64'));
+
+  var publicKey = privateKey.toPublicKey();
+
+  it('will error with incorrect message type', function() {
+    expect(function() {
+      return new Message(new Date());
+    }).to.throw('First argument should be a string');
+  });
+
+  it('will instantiate without "new"', function() {
+    var message = Message(text);
+    should.exist(message);
+  });
+
+  var signature2;
+  var signature3;
+
+  it('can sign a message', function() {
+    var message2 = new Message(text);
+    signature2 = message2._sign(privateKey);
+    signature3 = Message(text).sign(privateKey);
+    should.exist(signature2);
+    should.exist(signature3);
+  });
+
+  it('sign will error with incorrect private key argument', function() {
+    expect(function() {
+      var message3 = new Message(text);
+      return message3.sign('not a private key');
+    }).to.throw('First argument should be an instance of PrivateKey');
+  });
+
+  it('can verify a message with signature', function() {
+    var message4 = new Message(text);
+    var verified = message4._verify(publicKey, signature2);
+    verified.should.equal(true);
+  });
+
+  it('can verify a message with existing signature', function() {
+    var message5 = new Message(text);
+    var verified = message5._verify(publicKey, signature);
+    verified.should.equal(true);
+  });
+
+  it('verify will error with incorrect public key argument', function() {
+    expect(function() {
+      var message6 = new Message(text);
+      return message6._verify('not a public key', signature);
+    }).to.throw('First argument should be an instance of PublicKey');
+  });
+
+  it('verify will error with incorrect signature argument', function() {
+    expect(function() {
+      var message7 = new Message(text);
+      return message7._verify(publicKey, 'not a signature');
+    }).to.throw('Second argument should be an instance of Signature');
+  });
+
+  it('verify will correctly identify a bad signature', function() {
+    var message8 = new Message(text);
+    var verified = message8._verify(publicKey, badSignature);
+    should.exist(message8.error);
+    verified.should.equal(false);
+  });
+
+  it('can verify a message with address and generated signature string', function() {
+    var message9 = new Message(text);
+    var verified = message9.verify(address, signature3);
+    should.not.exist(message9.error);
+    verified.should.equal(true);
+  });
+
+  it('will not verify with address mismatch', function() {
+    var message10 = new Message(text);
+    var verified = message10.verify(badAddress, signatureString);
+    should.exist(message10.error);
+    verified.should.equal(false);
+  });
+
+  it('will verify with an uncompressed pubkey', function() {
+    var privateKey = new bitcore.PrivateKey('5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss');
+    var message = new Message('This is an example of a signed message.');
+    var signature = message.sign(privateKey);
+    var verified = message.verify(privateKey.toAddress(), signature);
+    verified.should.equal(true);
+  });
+
+  it('can chain methods', function() {
+    var verified = Message(text).verify(address, signatureString);
+    verified.should.equal(true);
+  });
+
+  describe('#json', function() {
+
+    it('roundtrip to-from-to', function() {
+      var json = new Message(text).toJSON();
+      var message = Message.fromJSON(json);
+      message.toString().should.equal(text);
+    });
+
+    it('checks that the string parameter is valid JSON', function() {
+      expect(function() {
+        return Message.fromJSON('¹');
+      }).to.throw();
+    });
+
+  });
+
+  describe('#toString', function() {
+
+    it('message string', function() {
+      var message = new Message(text);
+      message.toString().should.equal(text);
+    });
+
+    it('roundtrip to-from-to', function() {
+      var str = new Message(text).toString();
+      var message = Message.fromString(str);
+      message.toString().should.equal(text);
+    });
+
+  });
+
+  describe('#inspect', function() {
+
+    it('should output formatted output correctly', function() {
+      var message = new Message(text);
+      var output = '<Message: '+text+'>';
+      message.inspect().should.equal(output);
+    });
+
+  });
+
+
+  it('accepts Address for verification', function() {
+    var verified = Message(text)
+      .verify(new Address(address), signatureString);
+    verified.should.equal(true);
+  });
+
+});