code: protected org.bouncycastle.crypto.CipherParameters getBcCipherParameter(AsymmetricCipherParameters parameters)
      {
          if (parameters instanceof BcAsymmetricKeyParameters) {
              return ((BcAsymmetricKeyParameters) parameters).getParameters();
          }
  
          // TODO: convert parameters to compatible ones
          throw new UnsupportedOperationException("Cipher parameters are incompatible with this signer: "
              + parameters.getClass().getName());
      }
docs: Convert cipher parameters to Bouncy Castle equivalent.
  
  @param parameters some asymmetric cipher parameters.
  @return equivalent bouncy castle parameters.