byte[] ConvertToEncryptedMessage(NewCamdMessage message)
{
_logger.Debug($"Prepare message headers for {Name}");
var prepareData = new List <byte>();
prepareData.Add((byte)(message.MessageId >> 8));
prepareData.Add((byte)(message.MessageId & 0xFF));
prepareData.Add((byte)(message.ServiceId >> 8));
prepareData.Add((byte)(message.ServiceId & 0xFF));
prepareData.Add((byte)(message.ProviderId >> 16));
prepareData.Add((byte)((message.ProviderId >> 8) & 0xFF));
prepareData.Add((byte)(message.ProviderId & 0xFF));
prepareData.Add(0);
prepareData.Add(0);
prepareData.Add(0);
_logger.Debug($"Correct message headers for {Name}");
message.Data[0] = (byte)message.Type;
message.Data[1] = (byte)((message.Data[1] & 240) | (((message.Data.Length - 3) >> 8) & 255));
message.Data[2] = (byte)((message.Data.Length - 3) & 255);
_logger.Debug($"Copy {message.Data.Length} bytes into the buffer for {Name}");
prepareData.AddRange(message.Data);
//Fill up
while (prepareData.Count % 8 != 7)
{
prepareData.Add(0);
}
_logger.Debug($"Encrypt data before sending to {Name}");
var padding = new byte[8];
_random.NextBytes(padding);
//fill up bytes with padding data at the end
var bufferLen = prepareData.Count;
var paddingLen = (8 - ((bufferLen - 2) % 8)) % 8;
var prepareDataArray = prepareData.ToArray();
Buffer.BlockCopy(padding, 0, prepareDataArray, bufferLen - paddingLen, paddingLen);
prepareData = prepareDataArray.ToList();
//Add checksum
prepareData.Add(XorSum(prepareData.ToArray()));
var ivec = new byte[8];
_random.NextBytes(ivec);
var dataToEncrypt = prepareData.ToArray();
var encrypted = _crypto.Encrypt(dataToEncrypt, _keyblock, ivec).ToList();
var dataToSend = new List <byte>();
dataToSend.Add((byte)((encrypted.Count + ivec.Length) >> 8));
dataToSend.Add((byte)((encrypted.Count + ivec.Length) & 0xFF));
dataToSend.AddRange(encrypted);
dataToSend.AddRange(ivec);
return(dataToSend.ToArray());
}
#pragma warning disable CA1822 // Mark members as static
public void EncryptAndDecrypt()
#pragma warning restore CA1822 // Mark members as static
{
const string Unencoded = "Foo";
byte[] encoded = EncryptionHelpers.Encrypt(
Encoding.UTF8.GetBytes(Unencoded));
string decoded = Encoding.UTF8.GetString(
EncryptionHelpers.Decrypt(encoded));
Assert.Equal(Unencoded, decoded);
}