public async Task <BitArray> EvaluateAsync(IBatchEvaluableCircuit evaluable, InputPartyMapping inputMapping, OutputPartyMapping outputMapping, BitArray localInputValues)
{
if (inputMapping.NumberOfInputs != evaluable.Context.NumberOfInputGates)
{
throw new ArgumentException(
"The number of inputs in input mapping does not match the number of declared inputs in the circuit.",
nameof(inputMapping)
);
}
if (outputMapping.NumberOfOutputs != evaluable.Context.NumberOfOutputGates)
{
throw new ArgumentException(
"The number of outputs in output mapping does not match the number of declared outputs in the circuit.",
nameof(outputMapping)
);
}
SecretSharingBooleanCircuitEvaluator evaluator = new SecretSharingBooleanCircuitEvaluator(MultiPartySession, _multiplicativeSharing);
BitArray maskedInputs = await MaskInputs(inputMapping, localInputValues);
Task <Bit>[] inputTasks = maskedInputs.Select(Task.FromResult).ToArray();
Task <Bit>[] outputTasks = evaluable.Evaluate(evaluator, inputTasks);
BitArray maskedOutputs = new BitArray(await Task.WhenAll(outputTasks));
return(await UnmaskOutputs(outputMapping, maskedOutputs));
}
private async Task <BitArray> MaskInputs(InputPartyMapping inputMapping, BitArray localInputValues)
{
List <int>[] inputIds = new List <int> [MultiPartySession.NumberOfParties];
for (int partyId = 0; partyId < inputIds.Length; ++partyId)
{
inputIds[partyId] = new List <int>();
}
for (int inputId = 0; inputId < inputMapping.NumberOfInputs; ++inputId)
{
int partyId = inputMapping.GetAssignedParty(inputId);
if (partyId < 0 || partyId >= MultiPartySession.NumberOfParties)
{
throw new ArgumentException("Input mapping assigns inputs to party not participating in current session.", nameof(inputMapping));
}
inputIds[partyId].Add(inputId);
}
List <int> localInputIds = inputIds[MultiPartySession.LocalParty.Id];
if (localInputValues.Length != localInputIds.Count)
{
throw new ArgumentException(
"Number of provided inputs does not match the number of declared inputs in the circuit for the local party.",
nameof(localInputValues)
);
}
BitArray localSharesOfInput = new BitArray(inputMapping.NumberOfInputs);
// --- Share local inputs and send via network ---
if (localInputIds.Count > 0)
{
BitArray localSharesOfLocalInput = localInputValues.Clone();
foreach (ITwoPartyNetworkSession session in MultiPartySession.RemotePartySessions)
{
BitArray remoteSharesOfLocalInput = _cryptoContext.RandomNumberGenerator.GetBits(localInputIds.Count);
localSharesOfLocalInput.Xor(remoteSharesOfLocalInput);
await session.Channel.WriteMessageAsync(remoteSharesOfLocalInput.ToBytes());
}
for (int localInputId = 0; localInputId < localInputIds.Count; ++localInputId)
{
localSharesOfInput[localInputIds[localInputId]] = localSharesOfLocalInput[localInputId];
}
}
// --- Receive shares of remote inputs via network ---
foreach (ITwoPartyNetworkSession session in MultiPartySession.RemotePartySessions)
{
List <int> remoteInputIds = inputIds[session.RemoteParty.Id];
if (remoteInputIds.Count > 0)
{
BitArray localSharesOfRemoteInput = BitArray.FromBytes(await session.Channel.ReadMessageAsync(), remoteInputIds.Count);
if (localSharesOfRemoteInput.Length != remoteInputIds.Count)
{
throw new ProtocolException("Number of input shares received from remote party does not match number of declared inputs in the circuit.");
}
for (int remoteInputId = 0; remoteInputId < remoteInputIds.Count; ++remoteInputId)
{
localSharesOfInput[remoteInputIds[remoteInputId]] = localSharesOfRemoteInput[remoteInputId];
}
}
}
return(localSharesOfInput);
}
