Generating HMC SHA1 hash in Java Using a Secret Key (Private Key)

Below is the method :

void generateHMCSHA1(){



int counter= 1;

            String privateKey = "0123456789ABCDEF0123456789ABCDEF";

            byte[] result = null;

            MessageDigest md;

try {

md = MessageDigest.getInstance("SHA-1");

 byte[] keyBytes = md.digest(privateKey.getBytes("UTF-8"));



           SecretKey sk = new SecretKeySpec(keyBytes, "HmacSHA1");

           Mac mac = Mac.getInstance("HmacSHA1");

           mac.init(sk);

            result = mac.doFinal(String.valueOf(counter).getBytes("US_ASCII"));



           StringBuilder sb = new StringBuilder();

           for (byte b : result) {

               sb.append(String.format("%02X ", b));

           }

          

           System.out.println("      Key: " + privateKey + "\n");

       

           System.out.println("  Results: " +sb );

          

} catch (NoSuchAlgorithmException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (UnsupportedEncodingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (InvalidKeyException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}           



}

Output :

Key: 0123456789ABCDEF0123456789ABCDEF
 
Results: 38 92 62 29 80 04 C9 83 EE 87 97 B0 C0 FD 77 4C 69 F3 82