private bool IsMultStepShareLegal(MultStepBCaseShare recvShareFromPlayer_i, MultStepVerificationPoly recvVerifcationPolynomial)
{
if (!IsRecvShareLegal(recvShareFromPlayer_i))
{
return(false);
}
var RxPolynomial = recvVerifcationPolynomial.RxPolynomial;
Zp Ratpoint0 = Zp.EvalutePolynomialAtPoint(RxPolynomial, new Zp(Prime, 0));
if (!Ratpoint0.Equals(new Zp(Prime, 0)))
{
return(false);
}
int w = NumTheoryUtils.GetFieldMinimumPrimitive(Prime);
var w_InMyIndex = new Zp(Prime, NumTheoryUtils.ModPow(w, Party.Id, Prime));
Zp RjFromPublicPolynomial = Zp.EvalutePolynomialAtPoint(RxPolynomial, w_InMyIndex);
Zp temp = recvShareFromPlayer_i.AShare.ConstMul(recvShareFromPlayer_i.BShare).ConstSub(recvShareFromPlayer_i.AbShare);
Zp RjFromRecvPrivateInfo = w_InMyIndex.ConstMul(recvShareFromPlayer_i.RShare).ConstAdd(temp);
if (!RjFromPublicPolynomial.Equals(RjFromRecvPrivateInfo))
{
return(false);
}
return(true);
}
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));
}
private static Zp[] getWelchBerlekampConstraintVector(IList <Zp> XVlaues, IList <Zp> YVlaues, int n, int e, int prime)
{
var bVector = new Zp[n];
for (int i = 0; i < n; i++)
{
bVector[i] = new Zp(prime, NumTheoryUtils.ModPow(XVlaues[i].Value, e, prime) * YVlaues[i].Value);
}
return(bVector);
}
private static IList <Zp> GenerateF_i_xPolynomial(ZpMatrix f_x_y,
Zp secret, int playerNum)
{
int w = NumTheoryUtils.GetFieldMinimumPrimitive(secret.Prime);
int w_i = NumTheoryUtils.ModPow(w, playerNum, secret.Prime);
var y_values = new int[f_x_y.ColCount];
for (int i = 0; i < f_x_y.ColCount; i++)
{
y_values[i] = NumTheoryUtils.ModPow(w_i, i, secret.Prime);
}
return(f_x_y.MulMatrixByScalarsVector(y_values).SumMatrixRows());
}
private static IList <Zp> GenerateG_i_yPolynomial(ZpMatrix f_x_y,
Zp secret, int playerNum)
{
int w = NumTheoryUtils.GetFieldMinimumPrimitive(secret.Prime);
int w_i = NumTheoryUtils.ModPow(w, playerNum, secret.Prime);
var x_values = new Zp[f_x_y.RowCount];
for (int i = 0; i < f_x_y.RowCount; i++)
{
x_values[i] = new Zp(secret.Prime, NumTheoryUtils.ModPow(w_i, i, secret.Prime));
}
var tempArr = f_x_y.Times(new ZpMatrix(x_values, VectorType.Column)).ZpVector;
return(tempArr);
}
//public override void loadFromByteArrayNoHeader(BitStream bs, int prime)
//{
// if (bs.readBoolean())
// fi_x = bs.readList(prime);
// if (bs.readBoolean())
// gi_y = bs.readList(prime);
//}
//public override void writeToBitStreamNoHeader(BitStream bs)
//{
// bs.writeBoolean(fi_x != null);
// if (fi_x != null)
// bs.writeList(fi_x);
// bs.writeBoolean(gi_y != null);
// if (gi_y != null)
// bs.writeList(gi_y);
//}
//public override byte[] writeToByteArray()
//{
// var bs = new BitStream();
// bs.writeMessageType(MessageType.ZP_LISTS);
// writeToBitStreamNoHeader(bs);
// bs.close();
// return bs.ByteArray;
//}
public virtual IList <Zp> CalculateF_i_xValuesForPlayers(int numOfPlayers, int prime)
{
int w_i, w = NumTheoryUtils.GetFieldMinimumPrimitive(prime);
int value;
var f_i_xValues = new List <Zp>();
for (int playerNum = 0; playerNum < numOfPlayers; playerNum++)
{
w_i = NumTheoryUtils.ModPow(w, playerNum, prime);
value = 0;
for (int j = 0; j < fi_x.Count; j++)
{
value += NumTheoryUtils.ModPow(w_i, j, prime) * fi_x[j].Value;
}
f_i_xValues.Add(new Zp(prime, value));
}
return(f_i_xValues);
}