|
public static Recombine ( IList |
||
| sharedSecrets | IList |
|
| polyDeg | int | |
| prime | System.Numerics.BigInteger | |
| return | BigZp | |
public void Share(BigZp secret)
{
Debug.Assert(Prime == secret.Prime);
IList <BigZp> coeffs = null;
int polyDegree = (int)Math.Ceiling(DstQuorum.Size / 3.0) - 1;
// generate a random polynomial
var shares = BigShamirSharing.Share(secret, DstQuorum.Size, PolyDegree, out coeffs);
MG[] witnesses = null;
MG commitment = null;
if (PolyCommit != null)
{
commitment = BigShamirSharing.GenerateCommitment(DstQuorum.Size, coeffs.ToArray(), Prime, ref witnesses, PolyCommit);
}
else
{
witnesses = new MG[DstQuorum.Size];
}
Multicast(new CommitMsg(commitment), DstQuorum.Members);
// create share messages
var shareMsgs = new ShareWitnessMsg <BigZp> [DstQuorum.Size];
for (int i = 0; i < DstQuorum.Size; i++)
{
shareMsgs[i] = new ShareWitnessMsg <BigZp>(shares[i], witnesses[i]);
}
if (PolyCommit != null)
{
Debug.Assert(PolyCommit.VerifyEval(commitment, new BigZp(Prime, 2), shareMsgs[1].Share, shareMsgs[1].Witness));
}
Debug.Assert(BigShamirSharing.Recombine(shares, PolyDegree, Prime) == secret);
// send the i-th share message to the i-th party
Send(shareMsgs, DstQuorum.Members);
}
public override void HandleMessage(int fromId, Msg msg)
{
Debug.Assert(msg.Type == MsgType.Reconst);
ReconstRecv[fromId] = (msg as ShareMsg <BigZp>).Share;
if (ReconstRecv.Count == Quorum.Size)
{
// reconstruct the output
var orderedShares = ReconstRecv.OrderBy(p => p.Key).Select(p => p.Value).ToList();
int polyDegree = (int)Math.Ceiling(Quorum.Size / 3.0) - 1;
Result = BigShamirSharing.Recombine(orderedShares, polyDegree, Prime);
IsCompleted = true;
// Error-correction procedure
//var xValues = new List<BigZp>();
//for (int i = 1; i <= reconstRecv.Count; i++)
// xValues.Add(new BigZp(Prime, i));
//var fixedShares = WelchBerlekampDecoder.Decode(xValues, reconstRecv, PolyDegree, PolyDegree, Prime);
//// interpolate again
//return BigShamirSharing.Recombine(fixedShares, PolyDegree, Prime);
}
}
