docs: public byte[] unsign(byte[] data, Key key) throws AuditSigningException {
          byte[] unsignedData = null;
          if (data != null) {
              try {
                  unsignedData = decrypt(data, key);
              } catch (AuditDecryptionException ade) {
                  throw new AuditSigningException(ade);
              }
          } else {
              Tr.error(tc, "security.audit.message.digest.error");
              throw new AuditSigningException("MessageDigest is invalid");
          }
  
          return (unsignedData);
      }