/* this*=b mod Modulus */
public void Mul(FP b)
{
if ((long)XES * b.XES > (long)FEXCESS)
{
Reduce();
}
DBIG d = BIG.Mul(x, b.x);
x.Copy(Mod(d));
XES = 2;
}
/* Galbraith & Scott Method */
public static BIG[] GS(BIG e)
{
BIG[] u = new BIG[4];
if (ECP.CURVE_PAIRING_TYPE == ECP.BN)
{
int i, j;
BIG t = new BIG(0);
BIG q = new BIG(ROM.CURVE_Order);
BIG[] v = new BIG[4];
for (i = 0; i < 4; i++)
{
t.Copy(new BIG(ROM.CURVE_WB[i]));
DBIG d = BIG.Mul(t, e);
v[i] = new BIG(d.Div(q));
u[i] = new BIG(0);
}
u[0].Copy(e);
for (i = 0; i < 4; i++)
{
for (j = 0; j < 4; j++)
{
t.Copy(new BIG(ROM.CURVE_BB[j][i]));
t.Copy(BIG.ModMul(v[j], t, q));
u[i].Add(q);
u[i].Sub(t);
u[i].Mod(q);
}
}
}
else
{
BIG q = new BIG(ROM.CURVE_Order);
BIG x = new BIG(ROM.CURVE_Bnx);
BIG w = new BIG(e);
for (int i = 0; i < 3; i++)
{
u[i] = new BIG(w);
u[i].Mod(x);
w.Div(x);
}
u[3] = new BIG(w);
if (ECP.SIGN_OF_X == ECP.NEGATIVEX)
{
u[1].Copy(BIG.ModNeg(u[1], q));
u[3].Copy(BIG.ModNeg(u[3], q));
}
}
return(u);
}
/* convert to Montgomery n-residue form */
public void NRes()
{
if (MODTYPE != PSEUDO_MERSENNE && MODTYPE != GENERALISED_MERSENNE)
{
DBIG d = BIG.Mul(x, new BIG(ROM.R2modp)); //** Change **
x.Copy(Mod(d));
XES = 2;
}
else
{
XES = 1;
}
}
/* GLV method */
public static BIG[] Glv(BIG e)
{
BIG[] u = new BIG[2];
if (ECP.CURVE_PAIRING_TYPE == ECP.BN)
{
int i, j;
BIG t = new BIG(0);
BIG q = new BIG(ROM.CURVE_Order);
BIG[] v = new BIG[2];
for (i = 0; i < 2; i++)
{
t.Copy(new BIG(ROM.CURVE_W[i])); // why not just t=new BIG(ROM.CURVE_W[i]);
DBIG d = BIG.Mul(t, e);
v[i] = new BIG(d.Div(q));
u[i] = new BIG(0);
}
u[0].Copy(e);
for (i = 0; i < 2; i++)
{
for (j = 0; j < 2; j++)
{
t.Copy(new BIG(ROM.CURVE_SB[j][i]));
t.Copy(BIG.ModMul(v[j], t, q));
u[i].Add(q);
u[i].Sub(t);
u[i].Mod(q);
}
}
}
else
{
// -(x^2).P = (Beta.x,y)
BIG q = new BIG(ROM.CURVE_Order);
BIG x = new BIG(ROM.CURVE_Bnx);
BIG x2 = BIG.SMul(x, x);
u[0] = new BIG(e);
u[0].Mod(x2);
u[1] = new BIG(e);
u[1].Div(x2);
u[1].RSub(q);
}
return(u);
}
/* this*=y */
/* Now uses Lazy reduction */
public void Mul(FP2 y)
{
if ((long)(a.XES + b.XES) * (y.a.XES + y.b.XES) > (long)FP.FEXCESS)
{
if (a.XES > 1)
{
a.Reduce();
}
if (b.XES > 1)
{
b.Reduce();
}
}
DBIG pR = new DBIG(0);
BIG C = new BIG(a.x);
BIG D = new BIG(y.a.x);
pR.UCopy(new BIG(ROM.Modulus));
DBIG A = BIG.Mul(a.x, y.a.x);
DBIG B = BIG.Mul(b.x, y.b.x);
C.Add(b.x);
C.Norm();
D.Add(y.b.x);
D.Norm();
DBIG E = BIG.Mul(C, D);
DBIG F = new DBIG(A);
F.Add(B);
B.RSub(pR);
A.Add(B);
A.Norm();
E.Sub(F);
E.Norm();
a.x.Copy(FP.Mod(A));
a.XES = 3;
b.x.Copy(FP.Mod(E));
b.XES = 2;
}
