// Create key exchange material from key data.
 public override byte[] CreateKeyExchange(byte[] data)
 {
     if (keyContainer == null)
     {
         throw new CryptographicException
                   (_("Crypto_MissingKey"));
     }
     if (rng == null)
     {
         rng = new RNGCryptoServiceProvider();
     }
     return(keyContainer.EncryptOAEP(data, padding, rng));
 }