diff --git a/browserify/crypto-index.js b/browserify/crypto-index.js
index 9a4f4c9..652c2ee 100644
--- a/browserify/crypto-index.js
+++ b/browserify/crypto-index.js
@@ -4,29 +4,71 @@
   var createHash = require('create-hash');
   var pbkdf2 = require('pbkdf2');
   var aes = require('browserify-aes');
+  var ec = require('elliptic').ec('p256');
 
-  exports.sha256 = function (buf) {
-    var hash = createHash('sha256');
-    hash.update(buf);
-    hash.end();
-    return Promise.resolve(hash.read());
-  };
+  function sha256(buf) {
+    return createHash('sha256').update(buf).digest();
+  }
 
-  exports.encrypt = function (data, password, salt, iv) {
+  function encrypt(data, password, salt, iv) {
     // Derived AES key is 128 bit, and the function takes a size in bytes.
     var aesKey = pbkdf2.pbkdf2Sync(password, Buffer(salt), 8192, 16, 'sha256');
     var cipher = aes.createCipheriv('aes-128-gcm', aesKey, Buffer(iv));
-    var result = Buffer.concat([cipher.update(Buffer(data)), cipher.final(), cipher.getAuthTag()]);
-    return Promise.resolve(result);
-  };
 
-  exports.decrypt = function (data, password, salt, iv) {
+    return Buffer.concat([cipher.update(Buffer(data)), cipher.final(), cipher.getAuthTag()]);
+  }
+
+  function decrypt(data, password, salt, iv) {
     var aesKey = pbkdf2.pbkdf2Sync(password, Buffer(salt), 8192, 16, 'sha256');
     var decipher = aes.createDecipheriv('aes-128-gcm', aesKey, Buffer(iv));
 
     decipher.setAuthTag(Buffer(data.slice(-16)));
-    var result = Buffer.concat([decipher.update(Buffer(data.slice(0, -16))), decipher.final()]);
-    return Promise.resolve(result);
-  };
+    return Buffer.concat([decipher.update(Buffer(data.slice(0, -16))), decipher.final()]);
+  }
 
+  function convertBN(bn) {
+    if (bn.red) {
+      bn = bn.fromRed();
+    }
+    var b64 = bn.toArrayLike(Buffer).toString('base64');
+    return b64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=*$/, '');
+  }
+  function genEcdsaKeyPair() {
+    var key = ec.genKeyPair();
+    var pubJwk = {
+      key_ops: ['verify']
+    , kty: 'EC'
+    , crv: 'P-256'
+    , x: convertBN(key.getPublic().x)
+    , y: convertBN(key.getPublic().y)
+    };
+
+    var privJwk = JSON.parse(JSON.stringify(pubJwk));
+    privJwk.key_ops = ['sign'];
+    privJwk.d = convertBN(key.getPrivate());
+
+    return {privateKey: privJwk, publicKey: pubJwk};
+  }
+
+  function sign(jwk, msg) {
+    var key = ec.keyFromPrivate(Buffer(jwk.d, 'base64'));
+    var sig = key.sign(sha256(msg));
+    return Buffer.concat([Buffer(sig.r, 'hex'), Buffer(sig.s, 'hex')]);
+  }
+
+  function verify(jwk, msg, signature) {
+    var key = ec.keyFromPublic({x: Buffer(jwk.x, 'base64'), y: Buffer(jwk.y, 'base64')});
+    var sig = {
+      r: Buffer(signature.slice(0, signature.length/2))
+    , s: Buffer(signature.slice(signature.length/2))
+    };
+    return key.verify(sha256(msg), sig);
+  }
+
+  exports.sha256  = function () { return Promise.resolve(sha256.apply(this, arguments)); };
+  exports.encrypt = function () { return Promise.resolve(encrypt.apply(this, arguments)); };
+  exports.decrypt = function () { return Promise.resolve(decrypt.apply(this, arguments)); };
+  exports.sign    = function () { return Promise.resolve(sign.apply(this, arguments)); };
+  exports.verify  = function () { return Promise.resolve(verify.apply(this, arguments)); };
+  exports.genEcdsaKeyPair = function () { return Promise.resolve(genEcdsaKeyPair.apply(this, arguments)); };
 }());
diff --git a/gulpfile.js b/gulpfile.js
index 5cdc695..f5a8966 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -18,4 +18,8 @@
       .pipe(gulp.dest('./'))
       ;
   });
+
+  gulp.task('watch', function () {
+    gulp.watch('browserify/*.js', [ 'default' ]);
+  });
 }());
diff --git a/package.json b/package.json
index 6ae6ae3..192f7b7 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,8 @@
     "browserify": "^14.1.0",
     "browserify-aes": "^1.0.6",
     "btoa": "^1.1.2",
+    "create-hash": "^1.1.2",
+    "elliptic": "^6.4.0",
     "gulp": "^3.9.1",
     "gulp-cli": "^1.2.2",
     "gulp-rename": "^1.2.2",