diff --git a/index.js b/index.js
index 9a711a5c9..7371c59f6 100644
--- a/index.js
+++ b/index.js
@@ -15,9 +15,9 @@ privsec.buffer = Buffer;
 privsec.constants = require('./lib/constants');
 privsec.hash = require('./lib/hash');
 privsec.point = require('./lib/point');
+privsec.privkey = require('./lib/privkey');
 
 //privsec.key = require('lib/key');
-//privsec.privkey = require('lib/privkey');
 //privsec.pubkey = require('lib/pubkey');
 //privsec.script = require('lib/script');
 //privsec.scriptexec = require('lib/scriptexec');
diff --git a/lib/privkey.js b/lib/privkey.js
new file mode 100644
index 000000000..ecb74931c
--- /dev/null
+++ b/lib/privkey.js
@@ -0,0 +1,77 @@
+var bn = require('./bn');
+var point = require('./point');
+var constants = require('./constants');
+var base58check = require('./base58check');
+
+var Privkey = function(n, network, compressed) {
+  if (typeof n === 'undefined')
+    return;
+  this.setNumber(n);
+  this.setNetwork(network);
+  this.setCompressed(compressed);
+};
+
+Privkey.prototype.setNumber = function(n) {
+  if (!n.lt(point.getN()))
+    throw new Error('privkey: Number must be less than N');
+  this.n = n;
+};
+
+Privkey.prototype.setNetwork = function(network) {
+  if (typeof constants[network] === undefined)
+    throw new Error('privkey: Must specify the network ("mainnet" or "testnet")');
+  this.network = network;
+};
+
+Privkey.prototype.setCompressed = function(compressed) {
+  if (typeof compressed !== 'boolean')
+    throw new Error('privkey: Must specify whether the corresponding public key is compressed or not (true or false)');
+  this.compressed = compressed;
+};
+
+Privkey.prototype.toWIF = function() {
+  this.setNetwork(this.network);
+  this.setCompressed(this.compressed);
+
+  var network = this.network;
+  var compressed = this.compressed;
+
+  var privbuf = this.n.toBuffer({size: 32});
+  var buf;
+  if (compressed)
+    buf = Buffer.concat([new Buffer([constants[network].privkey]), this.n.toBuffer({size: 32}), new Buffer([0x01])]);
+  else
+    buf = Buffer.concat([new Buffer([constants[network].privkey]), this.n.toBuffer({size: 32})]);
+
+  return base58check.encode(buf);
+};
+
+Privkey.prototype.fromWIF = function(str) {
+  var buf = base58check.decode(str);
+
+  if (buf.length === 1 + 32 + 1 && buf[1 + 32 + 1 - 1] == 1)
+    this.compressed = true;
+  else if (buf.length === 1 + 32)
+    this.compressed = false;
+  else
+    throw new Error('privkey: Length of buffer must be 33 (uncompressed) or 34 (compressed)');
+
+  if (buf[0] === constants.mainnet.privkey)
+    this.network = 'mainnet';
+  else if (buf[0] === constants.testnet.privkey)
+    this.network = 'testnet';
+  else
+    throw new Error('privkey: Invalid network');
+
+  this.n = bn.fromBuffer(buf.slice(1, 32 + 1));
+};
+
+Privkey.prototype.toString = function() {
+  return this.toWIF();
+};
+
+Privkey.prototype.fromString = function(str) {
+  this.fromWIF(str);
+};
+
+module.exports = Privkey;
diff --git a/test/test.privkey.js b/test/test.privkey.js
new file mode 100644
index 000000000..db271f9df
--- /dev/null
+++ b/test/test.privkey.js
@@ -0,0 +1,74 @@
+var Privkey = require('../lib/privkey');
+var base58check = require('../lib/base58check');
+var bn = require('../lib/bn');
+var should = require('chai').should();
+
+describe('#privkey', function() {
+  var hex = '96c132224121b509b7d0a16245e957d9192609c5637c6228311287b1be21627a';
+  var buf = new Buffer(hex, 'hex');
+  var enctestnet = 'cSdkPxkAjA4HDr5VHgsebAPDEh9Gyub4HK8UJr2DFGGqKKy4K5sG';
+  var enctu = '92jJzK4tbURm1C7udQXxeCBvXHoHJstDXRxAMouPG1k1XUaXdsu';
+  var encmainnet = 'L2Gkw3kKJ6N24QcDuH4XDqt9cTqsKTVNDGz1CRZhk9cq4auDUbJy';
+  var encmu = '5JxgQaFM1FMd38cd14e3mbdxsdSa9iM2BV6DHBYsvGzxkTNQ7Un';
+  
+  it('should create an empty private key', function() {
+    var privkey = new Privkey();
+    should.exist(privkey);
+  });
+
+  it('should create a mainnet private key', function() {
+    var privkey = new Privkey(bn.fromBuffer(buf), 'mainnet', true);
+    privkey.toString().should.equal(encmainnet);
+  });
+
+  it('should create an uncompressed testnet private key', function() {
+    var privkey = new Privkey(bn.fromBuffer(buf), 'testnet', false);
+    privkey.toString().should.equal(enctu);
+  });
+
+  it('should create an uncompressed mainnet private key', function() {
+    var privkey = new Privkey(bn.fromBuffer(buf), 'mainnet', false);
+    privkey.toString().should.equal(encmu);
+  });
+
+  describe('#fromWIF', function() {
+
+    it('should parse this compressed testnet address correctly', function() {
+      var privkey = new Privkey();
+      privkey.fromWIF(encmainnet);
+      privkey.toWIF().should.equal(encmainnet);
+    });
+
+  });
+
+  describe('#toWIF', function() {
+
+    it('should parse this compressed testnet address correctly', function() {
+      var privkey = new Privkey();
+      privkey.fromWIF(enctestnet);
+      privkey.toWIF().should.equal(enctestnet);
+    });
+
+  });
+
+  describe('#fromString', function() {
+
+    it('should parse this uncompressed testnet address correctly', function() {
+      var privkey = new Privkey();
+      privkey.fromString(enctu);
+      privkey.toWIF().should.equal(enctu);
+    });
+
+  });
+
+  describe('#toString', function() {
+
+    it('should parse this uncompressed mainnet address correctly', function() {
+      var privkey = new Privkey();
+      privkey.fromString(encmu);
+      privkey.toString().should.equal(encmu);
+    });
+
+  });
+
+});