[JAVA] HMAC in various languages

HMAC SHA-256 sample. I will write more if I have time.

Secret key secret key · Target This is a pen. Signed with HMAC SHA-256. The output will be b4197908ed255480db6bbedb27426c89520bcd3b79c81006f70a94f415b43a43.

First Java.

package example.misc;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

public class HmacDemo {

    private static final String SECRET = "secret key";
    private static final String TEXT = "This is a pen.";

    public static void main(String[] args) throws Exception {
        String algo = "HMacSHA256";
        final SecretKeySpec keySpec = new SecretKeySpec(SECRET.getBytes(),
                algo);
        final Mac mac = Mac.getInstance(algo);
        mac.init(keySpec);
        final byte[] signBytes = mac.doFinal(TEXT.getBytes());
        for (byte signByte : signBytes) {
            System.out.printf("%02x", signByte & 0xff);
        }
        System.out.print("\n");

    }
}

The algorithm specification is redundant, but is there only such a way of writing? It would be nice if the hexadecimal output of the byte string could be made a little cleaner. The Base64 encoded library accepts byte strings as they are. In this case, it may be good.

Next is Python

#!/usr/bin/python3

import hashlib
import hmac

SECRET = "secret key"
TEXT = "This is a pen."

print(hmac.new(bytes(SECRET, 'ascii'), bytes(TEXT, 'ascii'), hashlib.sha256).hexdigest())

Next Ruby.

#!/usr/bin/ruby

require 'openssl'

SECRET = "secret key"
TEXT = "This is a pen."

puts OpenSSL::HMAC.digest(OpenSSL::Digest::Digest.new('sha256'),
  SECRET, TEXT).unpack("H*")