public void roundTripDetached()
{
EnvelopedMessage msg = new EnvelopedMessage(true, false);
msg.AddAttribute(HeaderKeys.Algorithm, AlgorithmValues.AES_GCM_128, true);
msg.AddAttribute(HeaderKeys.IV, CBORObject.FromObject(rgbIV96), false);
msg.SetContent(strContent);
Recipient r = new Recipient(key128, AlgorithmValues.Direct);
msg.AddRecipient(r);
msg.Encrypt();
byte[] content = msg.GetEncryptedContent();
byte[] rgb = msg.EncodeToBytes();
msg = (EnvelopedMessage)Message.DecodeFromBytes(rgb);
msg.SetEncryptedContent(content);
r = msg.RecipientList[0];
r.SetKey(key128);
msg.Decrypt(r);
}