code: protected byte[] sign(final byte[] value) {
          if (this.signingKey == null) {
              return value;
          }
          if ("RSA".equalsIgnoreCase(this.signingKey.getAlgorithm())) {
              return EncodingUtils.signJwsRSASha512(this.signingKey, value);
          }
          return EncodingUtils.signJwsHMACSha512(this.signingKey, value);
  
      }
docs: Sign the array by first turning it into a base64 encoded string.
  
  @param value the value
  @return the byte [ ]