I am now trying to encode the string using HMAC-SHA256 using Java. The encoded string required to match another set of encoded string generated by Python using hmac.new(mySecret, myPolicy, hashlib.sha256).hexdigest(). I have tried

    Mac sha256_HMAC = Mac.getInstance("HmacSHA256");SecretKeySpec secretKey = new SecretKeySpec(secret.getBytes(), "HmacSHA256");sha256_HMAC.init(secretKey);byte[] hash = sha256_HMAC.doFinal(policy.getBytes());byte[] hexB = new Hex().encode(hash);String check = Hex.encodeHexString(hash);String sha256 = DigestUtils.sha256Hex(secret.getBytes());

after I print them out, hash, hexB, check and sha256 didn't provide the same result as the following Python encryption method

hmac.new(mySecret, myPolicy, hashlib.sha256).hexdigest()

So, I have try to looking for the library or something that work similar to the above Python function. Can anybody help me out?

Are you sure your key and input are identical and correctly encoded in both java and python?

HMAC-SHA256 works the same on both platforms.

Java

Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
SecretKeySpec secretKey = new SecretKeySpec("1234".getBytes(), "HmacSHA256");
sha256_HMAC.init(secretKey);
byte[] hash = sha256_HMAC.doFinal("test".getBytes());
String check = Hex.encodeHexString(hash);
System.out.println(new String(check));Output
24c4f0295e1bea74f9a5cb5bc40525c8889d11c78c4255808be00defe666671f

Python

print hmac.new("1234", "test", hashlib.sha256).hexdigest();Output
24c4f0295e1bea74f9a5cb5bc40525c8889d11c78c4255808be00defe666671f