Compute HMAC-SHA512 with secret key in java

Question

I want to exactly build a function which produces a HMAC with a secret key like this site provides:

http://www.freeformatter.com/hmac-generator.html

The Java 8 lib only provides MessageDigest and KeyGenerator which both only support up to SH256.

Also, Google doesn't give me any result for an implementation to generate a HMAC.

Does someone know a implementation?

I have this code to generate an ordinary SH256 but I guess this doesn't help me much:

   public static String get_SHA_512_SecurePassword(String passwordToHash) throws Exception {     String generatedPassword = null;      MessageDigest md = MessageDigest.getInstance("SHA-512");     byte[] bytes = md.digest(passwordToHash.getBytes("UTF-8"));     StringBuilder sb = new StringBuilder();     for (int i = 0; i < bytes.length; i++) {         sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));     }     generatedPassword = sb.toString();     System.out.println(generatedPassword);     return generatedPassword; } 

Answer 1

The simplest way can be -

private static final String HMAC_SHA512 = "HmacSHA512";  private static String toHexString(byte[] bytes) {     Formatter formatter = new Formatter();     for (byte b : bytes) {         formatter.format("%02x", b);     }     return formatter.toString(); }  public static String calculateHMAC(String data, String key)     throws SignatureException, NoSuchAlgorithmException, InvalidKeyException {     SecretKeySpec secretKeySpec = new SecretKeySpec(key.getBytes(), HMAC_SHA512);     Mac mac = Mac.getInstance(HMAC_SHA512);     mac.init(secretKeySpec);     return toHexString(mac.doFinal(data.getBytes())); }  public static void main(String[] args) throws Exception {     String hmac = calculateHMAC("data", "key");     System.out.println(hmac); } 

You can change the HMAC_SHA512 variable to any of the Mac algorithm and the code will work the same way.