diff --git a/src/js/crypto/rsa.js b/src/js/crypto/rsa.js
index 2f73fdd..7e2c86c 100644
--- a/src/js/crypto/rsa.js
+++ b/src/js/crypto/rsa.js
@@ -73,20 +73,34 @@ app.crypto.RSA = function(forge) {
 		return privateKey.decrypt(ctUtf8);
 	};
 
-	this.sign = function(input) {
+	/**
+	 * Signs an Array of Base64 encoded parts with the private key
+	 * @param parts [Array] Array of Base64 encoded parts
+	 * @return [String] The Base64 encoded signature
+	 */
+	this.sign = function(parts) {
 		var sha = forge.md.sha256.create();
-		sha.update(input);
+		parts.forEach(function(i) {
+			sha.update(forge.util.decode64(i));
+		});
 
-		var sig = privateKey.sign(sha);
-		return forge.util.encode64(sig);
+		return forge.util.encode64(privateKey.sign(sha));
 	};
 
-	this.verify = function(input, sig) {
+	/**
+	 * Verifies an Array of Base64 encoded parts with the public key
+	 * @param parts [Array] Array of Base64 encoded parts
+	 * @param sig [String] The Base64 encoded signatrure
+	 * @return [bool] if the verification was successful
+	 */
+	this.verify = function(parts, sig) {
 		// parse base64 signature to utf8
 		var sigUtf8 = forge.util.decode64(sig);
 
 		var sha = forge.md.sha256.create();
-		sha.update(input);
+		parts.forEach(function(i) {
+			sha.update(forge.util.decode64(i));
+		});
 
 		return publicKey.verify(sha.digest().getBytes(), sigUtf8);
 	};
diff --git a/test/unit/rsa-test.js b/test/unit/rsa-test.js
index 30620c2..9b31b1f 100644
--- a/test/unit/rsa-test.js
+++ b/test/unit/rsa-test.js
@@ -40,11 +40,11 @@ test("Decrypt", 1, function() {
 });
 
 test("Sign", 1, function() {
-	rsa_test.sig = rsa_test.rsa.sign(rsa_test.test_message);
+	rsa_test.sig = rsa_test.rsa.sign([btoa('iv'), btoa(rsa_test.test_message)]);
 	ok(rsa_test.sig);
 });
 
 test("Verify", 1, function() {
-	var res = rsa_test.rsa.verify(rsa_test.test_message, rsa_test.sig);
+	var res = rsa_test.rsa.verify([btoa('iv'), btoa(rsa_test.test_message)], rsa_test.sig);
 	ok(res);
 });
\ No newline at end of file