public override SymmetricCipherResult ProcessPayload(IModeBlockCipherParameters param)
{
CheckPayloadRequirements(param.Payload);
if (param.Payload.BitLength / _engine.BlockSizeBits < PARTITIONS)
{
throw new ArgumentException($"CBCI mode needs at least {PARTITIONS} blocks of data");
}
var payloads = TdesPartitionHelpers.TriPartitionBitString(param.Payload);
var ivs = TdesPartitionHelpers.SetupIvs(param.Iv);
var key = param.Key.ToBytes();
var engineParam = new EngineInitParameters(param.Direction, key, param.UseInverseCipherMode);
_engine.Init(engineParam);
var outBuffer = GetOutputBuffer(param.Payload.BitLength);
if (param.Direction == BlockCipherDirections.Encrypt)
{
Encrypt(param, payloads, ivs, outBuffer);
}
else
{
Decrypt(param, payloads, ivs, outBuffer);
}
return(new SymmetricCipherResult(
new BitString(outBuffer).GetMostSignificantBits(param.Payload.BitLength)
));
}
private MCTResult <AlgoArrayResponse> Encrypt(IModeBlockCipherParameters param)
{
if (param.Payload.BitLength != 192)
{
throw new ArgumentException("Data must be 192 bits");
}
var ivs = TdesPartitionHelpers.SetupIvs(param.Iv);
var pts = TdesPartitionHelpers.TriPartitionBitString(param.Payload);
var responses = new List <AlgoArrayResponse> {
new AlgoArrayResponse {
IV = ivs[0],
Keys = param.Key,
PlainText = param.Payload
}
};
var lastCipherTexts = new List <BitString>();
var indexAtWhichToStartSaving = NUMBER_OF_ITERATIONS - NUMBER_OF_OUTPUTS_TO_SAVE;
for (var i = 0; i < NumberOfCases; i++)
{
for (var j = 0; j < NUMBER_OF_ITERATIONS; j++)
{
for (var k = 0; k < PARTITIONS; k++)
{
var result = _algo.ProcessPayload(new ModeBlockCipherParameters(
BlockCipherDirections.Encrypt,
responses[i].Keys,
ivs[k].XOR(pts[k])
)).Result;
pts[k] = ivs[k].GetDeepCopy();
ivs[k] = result.GetDeepCopy();
}
if (j >= indexAtWhichToStartSaving)
{
lastCipherTexts.Insert(0, ivs[NUMBER_OF_ITERATIONS - 1 - j].GetDeepCopy());
}
}
responses.Last().CipherText = ivs[0].ConcatenateBits(ivs[1]).ConcatenateBits(ivs[2]);
responses.Add(new AlgoArrayResponse
{
IV = ivs[0],
Keys = _keyMaker.MixKeys(new TDESKeys(responses[i].Keys.GetDeepCopy()), lastCipherTexts.ToList()).ToOddParityBitString(),
PlainText = pts[0].ConcatenateBits(pts[1].ConcatenateBits(pts[2]))
});
}
responses.RemoveAt(responses.Count() - 1);
return(new MCTResult <AlgoArrayResponse>(responses));
}