Convert HMAC function from Java to JavaScript

Question

I am tying to implement an HMAC function in NodeJS using this Java function as a reference:

private static String printMacAsBase64(byte[] macKey, String counter) throws Exception { // import AES 128 MAC_KEY SecretKeySpec signingKey = new SecretKeySpec(macKey, "AES"); // create new HMAC object with SHA-256 as the hashing algorithm Mac mac = Mac.getInstance("HmacSHA256"); mac.init(signingKey); // integer -> string -> bytes -> encrypted bytes byte[] counterMac = mac.doFinal(counter.getBytes("UTF-8")); // base 64 encoded string return DatatypeConverter.printBase64Binary(counterMac); }

From this I get HMAC of Qze5cHfTOjNqwmSSEOd9nEISOobheV833AncGJLin9Y=

I am getting a different value for the HMAC when passing the same counter and key through the HMAC algorithm in node. Here is my code to generate the hmac.

var decryptedMacKey = 'VJ/V173QE+4CrVvMQ2JqFg=='; var counter = 1; var hash = crypto .createHmac('SHA256',decryptedMacKey) .update(new Buffer(counter.toString(),'utf8'),'utf8') .digest('base64');

When I run this I get a MAC of nW5MKXhnGmgpYwV0qmQtkNBDrCbqQWQSkk02fiQBsGU=

I was unable to find any equivalent to the SecretKeySpec class in javascript so that may be the missing link.

I was also able to generate the same value as my program using this https://quickhash.com/ by selecting the algorithm Sha-256 and entering the decrypted mac key and counter.

Artjom B. · Accepted Answer · 2015-12-09 09:21:00Z

You forgot to decode the decryptedMacKey from a Base 64 representation:

var hash = crypto.createHmac('SHA256', new Buffer(decryptedMacKey, 'base64')) .update(new Buffer(counter.toString(),'utf8'),'utf8') .digest('base64');

gives:

 'Qze5cHfTOjNqwmSSEOd9nEISOobheV833AncGJLin9Y='

I knew I had to be overlooking something. I will give it a try. Thanks!

Collectives™ on Stack Overflow

Convert HMAC function from Java to JavaScript

1 Answer 1

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Related