public void TestRequiredBytes()
{
Assert.AreEqual(0, BitQuadrupleArray.RequiredBytes(0));
Assert.AreEqual(1, BitQuadrupleArray.RequiredBytes(1));
Assert.AreEqual(1, BitQuadrupleArray.RequiredBytes(2));
Assert.AreEqual(2, BitQuadrupleArray.RequiredBytes(3));
}
public Task <PreprocessedSenderBatch> PreprocessSenderAsync(IMessageChannel channel, int numberOfInvocations)
{
byte[] randomOptionsBuffer = _randomNumberGenerator.GetBytes(BitQuadrupleArray.RequiredBytes(numberOfInvocations));
BitQuadrupleArray randomOptions = BitQuadrupleArray.FromBytes(randomOptionsBuffer, numberOfInvocations);
return(_obliviousTransfer.SendAsync(channel, randomOptions, numberOfInvocations)
.ContinueWith(task => new PreprocessedSenderBatch(randomOptions)));
}
public async Task <BitArray> ReceiveAsync(IMessageChannel channel, QuadrupleIndexArray selectionIndices, int numberOfInvocations)
{
if (selectionIndices.Length != numberOfInvocations)
{
throw new ArgumentException("Provided selection indices must match the specified number of invocations.", nameof(selectionIndices));
}
if (_receiverBatch == null || _nextReceiverInstanceId + numberOfInvocations > _receiverBatch.NumberOfInstances)
{
throw new InvalidOperationException("Not enough preprocessed receiver data available.");
}
QuadrupleIndexArray deltaSelectionIndices = new QuadrupleIndexArray(numberOfInvocations);
for (int i = 0; i < numberOfInvocations; ++i)
{
int deltaSelectionIndex = (_receiverBatch.GetSelectionIndex(_nextReceiverInstanceId + i) - selectionIndices[i] + 4) % 4;
deltaSelectionIndices[i] = deltaSelectionIndex;
}
await channel.WriteMessageAsync(deltaSelectionIndices.ToBytes());
byte[] packedMaskedOptionQuadruples = await channel.ReadMessageAsync();
if (packedMaskedOptionQuadruples.Length != BitQuadrupleArray.RequiredBytes(numberOfInvocations))
{
throw new DesynchronizationException("Received incorrect number of masked option quadruples.");
}
BitQuadrupleArray maskedOptionQuadruples = BitQuadrupleArray.FromBytes(packedMaskedOptionQuadruples, numberOfInvocations);
BitArray selectedBits = new BitArray(numberOfInvocations);
for (int i = 0; i < numberOfInvocations; ++i)
{
BitQuadruple maskedOptions = maskedOptionQuadruples[i];
selectedBits[i] = maskedOptions[selectionIndices[i]] ^ _receiverBatch.GetSelectedOption(_nextReceiverInstanceId + i);
}
_nextReceiverInstanceId += numberOfInvocations;
return(selectedBits);
}
