public static MessageModel DecryptMessage(this MessageModel message)
{
if ((message.MessageFlags & MessageFlags.EncryptedMessage) != MessageFlags.EncryptedMessage)
{
return(message);
}
if (message.EncryptedMessage == null)
{
throw new Exception("Encrypted blob is missing");
}
if (UserSettingsModel.Instance.PrivateKey == null)
{
throw new Exception("Private key is missing");
}
try
{
using (MemoryStream stream = new MemoryStream(message.EncryptedMessage))
{
// Read the encrypted AES encryption keys
// encrypted using sender's public key and recipient's public key
byte[] encryptedDataKeyForRecipient = stream.ReadNextBlob();
byte[] encryptedDataKeyForSender = stream.ReadNextBlob();
// Decrypt my copy of the AES key
byte[] aesKey = RsaEncryption.DecryptMessage(message.IsMine ? encryptedDataKeyForSender : encryptedDataKeyForRecipient, UserSettingsModel.Instance.PrivateKey);
// Decrypt the message encrypted using the AES key
byte[] serializedMessage = AesEncryption.DecryptMessage(stream.ReadNextBlob(), aesKey);
// Deserialize the protobuf format
return(ProtoBuf.Serializer.Deserialize <MessageModel>(new MemoryStream(serializedMessage)));
}
}
catch (Exception)
{
return(null);
}
}
