class BittrexContentDigest extends BaseParamsDigest {

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

    super(secretKeyBase64, HMAC_SHA_512);
  }

  public static BittrexContentDigest createInstance(String secretKeyBase64) {<FILL_FUNCTION_BODY>}

  @Override
  public String digestParams(RestInvocation restInvocation) {
    MessageDigest md;
    try {
      md = MessageDigest.getInstance("SHA-512");
    } catch (NoSuchAlgorithmException e) {
      throw new IllegalArgumentException(e);
    }

    String content = restInvocation.getRequestBody();
    return DigestUtils.bytesToHex(md.digest(content.getBytes()));
  }
}


    return secretKeyBase64 == null ? null : new BittrexContentDigest(secretKeyBase64);
  
<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