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);
}
private IList <Zp> ConstructRxPolynomial(ShareDetails aSharesDetails,
ShareDetails bSharesDetails, ShareDetails abSharesDetails, ShareDetails rSharesDetails)
{
var fax = aSharesDetails.RandomPolynomial;
var fbx = bSharesDetails.RandomPolynomial;
var hx = abSharesDetails.RandomPolynomial;
var rx = rSharesDetails.RandomPolynomial;
var RxPolynomial = new Zp[2 * PolynomialDeg + 1];
/* Initialize RxPolynomial coefs with zeros */
for (int i = 0; i < 2 * PolynomialDeg + 1; i++)
{
RxPolynomial[i] = new Zp(Prime, 0);
}
/* First calculate fax*fbx - hx */
for (int i = 0; i < fax.Count; i++)
{
Zp temp = fax[i];
for (int j = 0; j < fax.Count; j++)
{
RxPolynomial[i + j].Add(temp.ConstMul(fbx[j]));
}
RxPolynomial[i].Sub(hx[i]);
}
/* Calculate x*rx+fax*fbx - hx*/
for (int i = 0; i < rx.Count; i++)
{
RxPolynomial[i + 1].Add(rx[i]);
}
return(new List <Zp>(RxPolynomial));
}
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;
}