Convert HMAC-SHA384 function from Java to JavaScript

Question

This is the java function that does the job.

 static byte[] HmacSHA384(String data, byte[] key) {
    try {
        mac.init(new SecretKeySpec(key, HMAC_ALGORITHM));
    } catch (InvalidKeyException e) {
        //throw new PWAINUnRecoverableException("Invalid key exception while mac init", e);
        throw new RuntimeException("Invalid key exception while mac init", e);
    }
    return mac.doFinal(data.getBytes(StandardCharsets.UTF_8));
}

I've already tried this answer with no luck.

Used crypto-js module also as:

const result = crypto_js.HmacSHA384(key, data).toString();
console.log(result.split('').map(getBytes)); // used this to match byte array from java output. No luck!

function getBytes(x) {return x.charCodeAt(0);}

Note that I'm using key as a String in JavaScript code as crypto_js.HmacSHA384 accepts String only and not a byte[]. But I've compared my string's byte[] with java code's byte[].

Output from JS code:

[97,104,69,80,106,49,121,83,100,87,120,56,76,65,101,71,54,52,81,110,104,108,72,55,54,56,112,104,56,109,72,101,68,43,83,70,73,89,54,81,71,53,49,98,48,119,115,117,72,83,112,117,99,110,107,76,113,78,105,73,76,107,120,82]

Output from Java code:

[-29, 76, -16, -110, -35, -87, 18, -53, -1, -105, -77, -96, -49, -110, 102, -74, -110, 31, -87, 115, 102, -43, 101, -89, -82, -8, 96, -99, -89, 103, -128, 104, -121, -107, -98, 18, -18, 85, 97, -121, 30, 91, -42, -11, -6, -58, -7, 113]

Both takes same input.

Any help will be appreciated. Thanks!

Answer 1

In JavaScript it's not so easy to output raw bytes. See the answer https://stackoverflow.com/a/29433028/7873775 for the details.

But the byte arrays will still be different in Java and JavaScript because in JavaScript the Uint8Array represents an array of 8-bit unsigned integers while in Java byte range is from -128 to 127.

So Uint8Array [132, 179] in Java byte[] is [-124, -77].

To output the HMAC value in JavaScript you need to encode it in either Hex or Base64.

Here is Java code using commons-codec library:

byte[] key = "Secret Passphrase".getBytes(StandardCharsets.UTF_8);
String valueToDigest = "Message";
byte[] hmac = new HmacUtils(HMAC_SHA_384, key).hmac(valueToDigest);
System.out.println(asList(hmac));
System.out.println(Hex.encodeHexString(hmac));
System.out.println(Base64.encodeBase64String(hmac));

The result:

• Hex: 84b318cc0232a370c1f8b8746afcb575fc2debc680122c7422fd425638896d0dcf9e905b8cd9c1d7aed8d5439a2a2328
• Base64: hLMYzAIyo3DB+Lh0avy1dfwt68aAEix0Iv1CVjiJbQ3PnpBbjNnB167Y1UOaKiMo

Here is code with CryptoJS library:

const CryptoJS = require("crypto-js");
const hash = CryptoJS.HmacSHA384("Message", "Secret Passphrase");
console.log(hash.toString(CryptoJS.enc.Hex));
console.log(hash.toString(CryptoJS.enc.Base64));

And the result is identical:

• Hex: 84b318cc0232a370c1f8b8746afcb575fc2debc680122c7422fd425638896d0dcf9e905b8cd9c1d7aed8d5439a2a2328
• Base64: hLMYzAIyo3DB+Lh0avy1dfwt68aAEix0Iv1CVjiJbQ3PnpBbjNnB167Y1UOaKiMo