code: protected void configureSigningKeyFromPrivateKeyResource(final String signingSecretKey) {
          val object = extractPrivateKeyFromResource(signingSecretKey);
          LOGGER.trace("Located signing key resource [{}]", signingSecretKey);
          setSigningKey(object);
      }
docs: Configure signing key from private key resource.
  
  @param signingSecretKey the signing secret key