public override void ReceiveEmail(long fromPseudonym, object message, MessageType type)
{
if (type == MessageType.JoinRequest)
{
// Join the protocol.
var distCount = distPseudonyms.Count;
if (distCount == 1)
{
SendEmail(distPseudonyms[0],
new BridgeJoinMessage(Pseudonym, new Zp(Simulator.Prime, Id)),
MessageType.BridgeJoin);
}
else
{
// Secret share my id among all distributors
var shares = ShamirSharing.Share(new Zp(Simulator.Prime, Id),
distCount, Simulator.PolynomialDegree);
Debug.Assert(shares.Count == distCount);
Debug.Assert(Id == ShamirSharing.Reconstruct(shares,
Simulator.PolynomialDegree, Simulator.Prime).Value,
"The secret is not reconstructible! There is probably an overflow in polynomial evaluation of the sharing phase in Shamir sharing.");
for (int i = 0; i < distCount; i++)
{
SendEmail(distPseudonyms[i], new BridgeJoinMessage(Pseudonym, shares[i]), MessageType.BridgeJoin);
}
}
}
else
{
throw new Exception("Invalid email received.");
}
}
protected override Zp GetRecombinedResult(IList <Zp> recvList, int prime)
{
// Scan recvList - if there are null elements replace them arbitrarily to Zp with zero value
for (int i = 0; i < recvList.Count; i++)
{
if (recvList[i] == null)
{
recvList[i] = new Zp(prime, 0);
}
}
var xVlaues = new List <Zp>();
int w = NumTheoryUtils.GetFieldMinimumPrimitive(prime);
for (int i = 0; i < recvList.Count; i++)
{
xVlaues.Add(new Zp(prime, NumTheoryUtils.ModPow(w, i, prime)));
}
// Should call Welch-Berlekamp Decoder to fix error at last stage
var fixedShares = WelchBerlekampDecoder.Decode(xVlaues, recvList, PolynomialDeg, PolynomialDeg, prime);
if (fixedShares == null)
{
throw new Exception("There were more then polynomialDegree = " + PolynomialDeg + " Cheaters - cannot extract results.");
}
return(ShamirSharing.Recombine(fixedShares, PolynomialDeg, prime, true));
}
/// <summary>
/// Implementation according to GRR.
/// </summary>
public virtual void RunReductionRandomization(Zp oldSecret)
{
// randomize the coeficients
// generate a t degree polynomial, hi(x),
// with a free coef that equals 'ab' and create share for users from it.
var sharesValues = ShamirSharing.Share(oldSecret, NumParties, PolynomialDeg);
var shareMsgs = new List <ShareMsg <Zp> >();
foreach (var shareValue in sharesValues)
{
shareMsgs.Add(new ShareMsg <Zp>(new Share <Zp>(shareValue), Stage.RandomizationReceive));
}
// send to the j-th user hi(j) and receive from every other k player hk(i)
Send(shareMsgs);
OnReceive((int)Stage.RandomizationReceive,
delegate(List <Msg> shares)
{
var vanderFirstRow =
ZpMatrix.GetSymmetricVanderMondeMatrix(NumParties, Prime)
.Transpose.Inverse.GetMatrixRow(0);
// Calculate the value of the polynomial H(x) at i = H(i) as defined at GRR
var tempSecret = new Zp(Prime, 0);
for (int i = 0; i < NumParties; i++)
{
tempSecret.Add(((shares[i] as ShareMsg <Zp>).Share as Share <Zp>).Value.Mul(vanderFirstRow[i]));
}
});
}
protected void ShareSecret(Zp secret, IList <int> players, DkmsKey key)
{
var shares = ShamirSharing.Share(secret, players.Count, players.Count - 1);
var shareMsgs = new List <ShareMsg <Zp> >();
foreach (var share in shares)
{
shareMsgs.Add(new ShareMsg <Zp>(new Share <Zp>(share), key));
}
Send(players, shareMsgs);
}
//public override void Receive<BrideAssignment>(int fromNode, BrideAssignment message, MessageType type)
//{
// throw new NotImplementedException();
//}
public override void ReceiveEmail(long fromPseudonym, object message, MessageType type)
{
if (type == MessageType.UserAssignments) // From a distributor: Here's a list of bridge id share for you.
{
var assignments = message as List <UserAssignment>;
if (distributorPseudonyms.Count == 1)
{
foreach (var a in assignments)
{
Bridges.Add(Simulator.GetNode <Bridge>((int)a.BridgeShare.Value));
}
}
else
{
foreach (var a in assignments)
{
if (!BridgeShares.ContainsKey(a.BridgePseudonym))
{
BridgeShares[a.BridgePseudonym] = new List <Zp>();
}
BridgeShares[a.BridgePseudonym].Add(a.BridgeShare);
if (BridgeShares[a.BridgePseudonym].Count == distributorPseudonyms.Count)
{
// We have enough number of shares to reconstruct the bridge ID
int bridgeId = (int)ShamirSharing.Reconstruct(BridgeShares[a.BridgePseudonym],
Simulator.PolynomialDegree, Simulator.Prime).Value;
Debug.Assert(Simulator.GetNodes <Bridge>().Any(b => b.Id == bridgeId), "Invalid bridge ID reconstructed from shares.");
Bridges.Add(Simulator.GetNode <Bridge>(bridgeId));
BridgeShares[a.BridgePseudonym] = null;
}
}
}
}
else
{
throw new Exception("Invalid message received.");
}
}
static void Main(string[] args)
{
Console.WriteLine("Started.");
StaticRandom.Init(seed);
int quorumSize = 20;
int degree = quorumSize / 3;
var secret = new Zp(Prime, 3);
var shareMatrix = ZpMatrix.GetIdentityMatrix(quorumSize, Prime);
// create the initial shares
var initalShares = ShamirSharing.Share(secret, quorumSize, degree);
for (var i = 0; i < quorumSize; i++)
{
IList <Zp> reshares = QuorumSharing.CreateReshares(initalShares[i], quorumSize, degree);
for (var j = 0; j < quorumSize; j++)
{
shareMatrix.SetMatrixCell(j, i, reshares[j]);
}
}
// combine the reshares
List <Zp> finalShares = new List <Zp>();
for (var i = 0; i < quorumSize; i++)
{
Zp finalShare = QuorumSharing.CombineReshares(shareMatrix.GetMatrixRow(i), quorumSize, Prime);
finalShares.Add(finalShare);
}
// combine the shares
Zp final = ShamirSharing.Recombine(finalShares, degree, Prime);
Console.WriteLine(final.Value);
Console.WriteLine("Press any key to continue...");
Console.ReadKey();
}
public override void Run()
{
// secret-share my input among all parties
var sharesValues = ShamirSharing.Share(Input, NumParties, PolynomialDeg);
var shareMsgs = new List <ShareMsg <Zp> >();
foreach (var shareValue in sharesValues)
{
shareMsgs.Add(new ShareMsg <Zp>(new Share <Zp>(shareValue), Stage.InputReceive));
}
Send(shareMsgs);
OnReceive((int)Stage.InputReceive,
delegate(List <Msg> shares)
{
int k = 1; // TODO: temp only - needed to be index of gate
foreach (var gate in Circuit.Gates)
{
RunGateComputation(gate, GetZps(shares.Cast <ShareMsg <Zp> >()), k + ".");
k++;
}
var resultList = new SortedDictionary <int, Zp>();
FilterPlayers(PartyIds); // remove unwanted players if necessary
// share the result with all players
SendToAll(new ShareMsg <Zp>(new Share <Zp>(Circuit.Output), Stage.ResultReceive));
OnReceive((int)Stage.ResultReceive,
delegate(List <Msg> resMsgs)
{
Result = GetRecombinedResult(GetZps(resMsgs.OrderBy(s => s.SenderId).Cast <ShareMsg <Zp> >()), Input.Prime);
if (MpcFinish != null)
{
MpcFinish(StateKey);
}
});
});
}
// TODO: Mahdi: Should this method be virtual?
protected virtual Zp GetRecombinedResult(IList <Zp> recvList, int prime)
{
return(ShamirSharing.Recombine(recvList, PolynomialDeg, prime));
}
