class KrakenDigest extends BaseParamsDigest {

  /**
   * Constructor
   *
   * @param secretKeyBase64
   * @throws IllegalArgumentException if key is invalid (cannot be base-64-decoded or the decoded
   *     key is invalid).
   */
  private KrakenDigest(byte[] secretKeyBase64) {

    super(secretKeyBase64, HMAC_SHA_512);
  }

  public static KrakenDigest createInstance(String secretKeyBase64) {

    if (secretKeyBase64 != null) {
      return new KrakenDigest(Base64.getDecoder().decode(secretKeyBase64.getBytes()));
    } else return null;
  }

  @Override
  public String digestParams(RestInvocation restInvocation) {<FILL_FUNCTION_BODY>}
}


    MessageDigest sha256;
    try {
      sha256 = MessageDigest.getInstance("SHA-256");
    } catch (NoSuchAlgorithmException e) {
      throw new RuntimeException(
          "Illegal algorithm for post body digest. Check the implementation.");
    }
    sha256.update(restInvocation.getParamValue(FormParam.class, "nonce").toString().getBytes());
    sha256.update(restInvocation.getRequestBody().getBytes());

    Mac mac512 = getMac();
    mac512.update(("/" + restInvocation.getPath()).getBytes());
    mac512.update(sha256.digest());

    return Base64.getEncoder().encodeToString(mac512.doFinal()).trim();
  
<methods>public javax.crypto.Mac getMac() <variables>public static final java.lang.String HMAC_MD5,public static final java.lang.String HMAC_SHA_1,public static final java.lang.String HMAC_SHA_256,public static final java.lang.String HMAC_SHA_384,public static final java.lang.String HMAC_SHA_512,private final non-sealed javax.crypto.Mac mac