pubkey

index.js

@@ -16,9 +16,9 @@ privsec.constants = require('./lib/constants');
 privsec.hash = require('./lib/hash');
 privsec.point = require('./lib/point');
 privsec.privkey = require('./lib/privkey');
+privsec.pubkey = require('./lib/pubkey');
 
 //privsec.key = require('lib/key');
-//privsec.pubkey = require('lib/pubkey');
 //privsec.script = require('lib/script');
 //privsec.scriptexec = require('lib/scriptexec');
 //privsec.tx = require('lib/tx');

lib/pubkey.js

@@ -0,0 +1,67 @@
+var point = require('./point');
+var bn = require('./bn');
+
+var Pubkey = function(p) {
+  this.p = p;
+};
+
+Pubkey.prototype.fromDER = function(buf) {
+  if (buf[0] == 0x04) {
+    var xbuf = buf.slice(1, 33);
+    var ybuf = buf.slice(33, 65);
+    if (xbuf.length !== 32 || ybuf.length !== 32 || buf.length !== 65)
+      throw new Error('pubkey: Length of x and y must be 32 bytes');
+    var x = bn(xbuf);
+    var y = bn(ybuf);
+    this.p = point(x, y);
+  } else if (buf[0] == 0x03) {
+    var xbuf = buf.slice(1);
+    var x = bn(xbuf);
+    this.fromX(true, x);
+  } else if (buf[0] == 0x02) {
+    var xbuf = buf.slice(1);
+    var x = bn(xbuf);
+    this.fromX(false, x);
+  } else {
+    throw new Error('pubkey: Invalid DER format pubkey');
+  }
+};
+
+Pubkey.prototype.fromString = function(str) {
+  this.fromDER(new Buffer(str, 'hex'));
+};
+
+Pubkey.prototype.fromX = function(odd, x) {
+  if (typeof odd !== 'boolean')
+    throw new Error('pubkey: Must specify whether y is odd or not (true or false)');
+  this.p = point.fromX(odd, x);
+};
+
+Pubkey.prototype.toDER = function(compressed) {
+  if (typeof compressed !== 'boolean')
+    throw new Error('pubkey: Must specify whether the public key is compressed or not (true or false)');
+
+  var x = this.p.getX();
+  var y = this.p.getY();
+
+  var xbuf = x.toBuffer({size: 32});
+  var ybuf = y.toBuffer({size: 32});
+
+  if (!compressed) {
+    var prefix = new Buffer([0x04]);
+    return Buffer.concat([prefix, xbuf, ybuf]);
+  } else {
+    var odd = ybuf[ybuf.length - 1] % 2;
+    if (odd)
+      var prefix = new Buffer([0x03]);
+    else
+      var prefix = new Buffer([0x02]);
+    return Buffer.concat([prefix, xbuf]);
+  }
+};
+
+Pubkey.prototype.toString = function() {
+  return this.toDER(true).toString('hex');
+};
+
+module.exports = Pubkey;

test/test.pubkey.js

@@ -0,0 +1,96 @@
+var should = require('chai').should();
+var pubkey = require('../lib/pubkey');
+var point = require('../lib/point');
+var bn = require('../lib/bn');
+
+describe('pubkey', function() {
+  
+  it('should create a blank public key', function() {
+    var pk = new pubkey();
+    should.exist(pk);
+  });
+
+  it('should create a public key with a point', function() {
+    var p = point();
+    var pk = new pubkey(p);
+    should.exist(pk.p);
+  });
+
+  describe('#fromDER', function() {
+    
+    it('should parse this uncompressed public key', function() {
+      var pk = new pubkey();
+      pk.fromDER(new Buffer('041ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341', 'hex'));
+      pk.p.getX().toString(16).should.equal('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a');
+      pk.p.getY().toString(16).should.equal('7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341');
+    });
+
+    it('should parse this compressed public key', function() {
+      var pk = new pubkey();
+      pk.fromDER(new Buffer('031ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a', 'hex'));
+      pk.p.getX().toString(16).should.equal('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a');
+      pk.p.getY().toString(16).should.equal('7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341');
+    });
+
+    it('should throw an error on this invalid public key', function() {
+      var pk = new pubkey();
+      (function() {
+        pk.fromDER(new Buffer('091ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a', 'hex'));
+      }).should.throw();
+    });
+
+  });
+
+  describe('#fromString', function() {
+
+    it('should parse this known valid public key', function() {
+      pk = new pubkey();
+      pk.fromString('041ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341');
+      pk.p.getX().toString(16).should.equal('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a');
+      pk.p.getY().toString(16).should.equal('7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341');
+    });
+
+  });
+
+  describe('#fromX', function() {
+    
+    it('should create this known public key', function() {
+      var x = bn.fromBuffer(new Buffer('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a', 'hex'));
+      var pk = new pubkey();
+      pk.fromX(true, x);
+      pk.p.getX().toString(16).should.equal('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a');
+      pk.p.getY().toString(16).should.equal('7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341');
+    });
+
+  });
+
+  describe('#toDER', function() {
+
+    it('should return this compressed DER format', function() {
+      var x = bn.fromBuffer(new Buffer('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a', 'hex'));
+      var pk = new pubkey();
+      pk.fromX(true, x);
+      pk.toDER(true).toString('hex').should.equal('031ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a');
+    });
+
+    it('should return this uncompressed DER format', function() {
+      var x = bn.fromBuffer(new Buffer('1ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a', 'hex'));
+      var pk = new pubkey();
+      pk.fromX(true, x);
+      pk.toDER(false).toString('hex').should.equal('041ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341');
+    });
+
+  });
+
+  describe('#toString', function() {
+    
+    it('should print this known public key', function() {
+      var hex = '031ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a';
+      var pk = new pubkey();
+      pk.fromString(hex);
+      pk.toString().should.equal(hex);
+    });
+
+  });
+
+});