Fix bug: crypto.Decipher#update() returns string, not void

node/node-tests.ts

@@ -99,6 +99,20 @@ function stream_readable_pipe_test() {
 
 var hmacResult: string = crypto.createHmac('md5', 'hello').update('world').digest('hex');
 
+function crypto_cipher_decipher_string_test() {
+	var key:Buffer = new Buffer([1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7]);
+	var clearText:string = "This is the clear text.";
+	var cipher:crypto.Cipher = crypto.createCipher("aes-128-ecb", key);
+	var cipherText:string = cipher.update(clearText, "utf8", "hex");
+	cipherText += cipher.final("hex");
+
+	var decipher:crypto.Decipher = crypto.createDecipher("aes-128-ecb", key);
+	var clearText2:string = decipher.update(cipherText, "hex", "utf8");
+	clearText2 += decipher.final("utf8");
+
+	assert.equal(clearText2, clearText);
+}
+
 ////////////////////////////////////////////////////
 
 // Make sure .listen() and .close() retuern a Server instance

node/node.d.ts

@@ -1083,7 +1083,7 @@ declare module "crypto" {
     export function createDecipher(algorithm: string, password: any): Decipher;
     export function createDecipheriv(algorithm: string, key: any, iv: any): Decipher;
     interface Decipher {
-        update(data: any, input_encoding?: string, output_encoding?: string): void;
+        update(data: any, input_encoding?: string, output_encoding?: string): string;
         final(output_encoding?: string): string;
         setAutoPadding(auto_padding: boolean): void;
     }