diff --git a/src/js/crypto/crypto.js b/src/js/crypto/crypto.js
index d087e62..0fad4d1 100644
--- a/src/js/crypto/crypto.js
+++ b/src/js/crypto/crypto.js
@@ -81,12 +81,13 @@ app.crypto.Crypto = function(window, util) {
 	/**
 	 * Derive an asymmetric keypait from the user's secret
 	 */
-	this.deriveKeyPair = function(naclCrypto) {
-		var keys = naclCrypto.generateKeypair(symmetricUserKey);
-		if (keyId) {
-			keys.id = keyId;
-		}
-		return keys;
+	this.deriveKeyPair = function(naclCrypto, callback) {
+		naclCrypto.generateKeypair(symmetricUserKey, function(keys) {
+			if (keyId) {
+				keys.id = keyId;
+			}
+			callback(keys);
+		});
 	};
 
 	//
diff --git a/src/js/crypto/nacl-crypto.js b/src/js/crypto/nacl-crypto.js
index 8b0f6f1..d2eb5cc 100644
--- a/src/js/crypto/nacl-crypto.js
+++ b/src/js/crypto/nacl-crypto.js
@@ -8,21 +8,49 @@ var NaclCrypto = function(nacl, util) {
 	 * Generates a baes64 encoded keypair for use with NaCl
 	 * @param seed [String] A base64 encoded (pseudo) random seed e.g. PBKDF2
 	 */
-	this.generateKeypair = function(seed) {
-		var keys;
+	this.generateKeypair = function(seed, callback) {
+		var keys, seedBuf;
 
 		if (seed) {
-			var seedBuf = nacl.encode_latin1(util.base642Str(seed));
-			keys = nacl.crypto_box_keypair_from_seed(seedBuf);
-		} else {
-			keys = nacl.crypto_box_keypair();
-		}
+			// do key deterministic derivation from pseudo random seed
+			seedBuf = nacl.encode_latin1(util.base642Str(seed));
 
-		return {
-			id: util.UUID(),
-			boxPk: util.str2Base64(nacl.decode_latin1(keys.boxPk)),
-			boxSk: util.str2Base64(nacl.decode_latin1(keys.boxSk))
-		};
+			if (Worker) {
+
+				var worker = new Worker(app.config.workerPath + '/crypto/nacl-worker.js');
+				worker.onmessage = function(e) {
+					callback({
+						id: util.UUID(),
+						boxPk: util.str2Base64(nacl.decode_latin1(e.data.boxPk)),
+						boxSk: util.str2Base64(nacl.decode_latin1(e.data.boxSk))
+					});
+				};
+				worker.postMessage({
+					type: 'keygen',
+					seed: seedBuf
+				});
+
+			} else {
+				// no web worker support
+				keys = nacl.crypto_box_keypair_from_seed(seedBuf);
+
+				callback({
+					id: util.UUID(),
+					boxPk: util.str2Base64(nacl.decode_latin1(keys.boxPk)),
+					boxSk: util.str2Base64(nacl.decode_latin1(keys.boxSk))
+				});
+			}
+
+		} else {
+			// generate keypiar from random values
+			keys = nacl.crypto_box_keypair();
+
+			callback({
+				id: util.UUID(),
+				boxPk: util.str2Base64(nacl.decode_latin1(keys.boxPk)),
+				boxSk: util.str2Base64(nacl.decode_latin1(keys.boxSk))
+			});
+		}
 	};
 
 	/**
diff --git a/src/js/crypto/nacl-worker.js b/src/js/crypto/nacl-worker.js
index 4a99613..7fada0d 100644
--- a/src/js/crypto/nacl-worker.js
+++ b/src/js/crypto/nacl-worker.js
@@ -13,7 +13,15 @@
 		var args = e.data,
 			output = null;
 
-		if (args.type === 'encrypt' && args.plaintext && args.nonce && args.recipientPk && args.senderSk) {
+		if (args.type === 'keygen') {
+			// generate keypair
+			if (args.seed) {
+				output = nacl.crypto_box_keypair_from_seed(args.seed);
+			} else {
+				output = nacl.crypto_box_keypair();
+			}
+
+		} else if (args.type === 'encrypt' && args.plaintext && args.nonce && args.recipientPk && args.senderSk) {
 			// start encryption
 			output = nacl.crypto_box(args.plaintext, args.nonce, args.recipientPk, args.senderSk);
 
diff --git a/src/js/dao/email-dao.js b/src/js/dao/email-dao.js
index a211664..a09f738 100644
--- a/src/js/dao/email-dao.js
+++ b/src/js/dao/email-dao.js
@@ -36,15 +36,18 @@ app.dao.EmailDAO = function(_, crypto, devicestorage, cloudstorage, naclCrypto,
 
 		function initNaclCrypto() {
 			// derive keypair from user's secret key
-			keypair = crypto.deriveKeyPair(naclCrypto);
-			//publish public key to cloud service
-			var pubkey = new app.model.PublicKey({
-				_id: keypair.id,
-				userId: account.get('emailAddress'),
-				publicKey: keypair.boxPk
-			});
-			cloudstorage.putPublicKey(pubkey.toJSON(), function(err) {
-				callback(err);
+			crypto.deriveKeyPair(naclCrypto, function(generated) {
+				keypair = generated;
+
+				//publish public key to cloud service
+				var pubkey = new app.model.PublicKey({
+					_id: keypair.id,
+					userId: account.get('emailAddress'),
+					publicKey: keypair.boxPk
+				});
+				cloudstorage.putPublicKey(pubkey.toJSON(), function(err) {
+					callback(err);
+				});
 			});
 		}
 	};
diff --git a/test/unit/nacl-crypto-test.js b/test/unit/nacl-crypto-test.js
index d2d7aa5..215ea5e 100644
--- a/test/unit/nacl-crypto-test.js
+++ b/test/unit/nacl-crypto-test.js
@@ -14,22 +14,30 @@ test("Init", 1, function() {
 	nacl_test.crypto = new app.crypto.NaclCrypto(nacl, nacl_test.util);
 });
 
-test("Generate Keypair from seed", 1, function() {
+asyncTest("Generate Keypair from seed", 1, function() {
 	// generate keypair from seed
 	var seed = nacl_test.util.random(128);
-	var keys = nacl_test.crypto.generateKeypair(seed);
-	ok(keys.boxSk && keys.boxPk && keys.id, "Keypair: " + JSON.stringify(keys));
+	nacl_test.crypto.generateKeypair(seed, function(keys) {
+		ok(keys.boxSk && keys.boxPk && keys.id, "Keypair: " + JSON.stringify(keys));
+
+		start();
+	});
 });
 
-test("Generate Keypair", 2, function() {
+asyncTest("Generate Keypair", 2, function() {
 	// generate keypair
-	var senderKeypair = nacl_test.crypto.generateKeypair();
-	ok(senderKeypair.boxSk && senderKeypair.boxPk, "Sender keypair: " + JSON.stringify(senderKeypair));
-	var recipientKeypair = nacl_test.crypto.generateKeypair();
-	ok(recipientKeypair.boxSk && recipientKeypair.boxPk, "Receiver keypair: " + JSON.stringify(recipientKeypair));
+	nacl_test.crypto.generateKeypair(null, function(senderKeypair) {
+		ok(senderKeypair.boxSk && senderKeypair.boxPk, "Sender keypair: " + JSON.stringify(senderKeypair));
 
-	nacl_test.senderKeypair = senderKeypair;
-	nacl_test.recipientKeypair = recipientKeypair;
+		nacl_test.crypto.generateKeypair(null, function(recipientKeypair) {
+			ok(recipientKeypair.boxSk && recipientKeypair.boxPk, "Receiver keypair: " + JSON.stringify(recipientKeypair));
+
+			nacl_test.senderKeypair = senderKeypair;
+			nacl_test.recipientKeypair = recipientKeypair;
+
+			start();
+		});
+	});
 });
 
 test("Asymmetric En/Decrypt (Synchronous)", 3, function() {