/* this*=c mod Modulus, where c is a small int */
public void imul(int c)
{
norm();
bool s = false;
if (c < 0)
{
c = -c;
s = true;
}
long afx = (BIG.EXCESS(x) + 1) * (c + 1) + 1;
if (c < ROM.NEXCESS && afx < ROM.FEXCESS)
{
x.imul(c);
}
else
{
if (afx < ROM.FEXCESS)
{
x.pmul(c);
}
else
{
DBIG d = x.pxmul(c);
x.copy(d.mod(p));
}
}
if (s)
{
neg();
}
norm();
}
/* Optimal R-ate pairing */
public static FP12 ate(ECP2 P, ECP Q)
{
FP2 f = new FP2(new BIG(ROM.CURVE_Fra), new BIG(ROM.CURVE_Frb));
BIG x = new BIG(ROM.CURVE_Bnx);
BIG n = new BIG(x);
ECP2 K = new ECP2();
FP12 lv;
n.pmul(6);
n.dec(2);
n.norm();
P.affine();
Q.affine();
FP Qx = new FP(Q.getx());
FP Qy = new FP(Q.gety());
ECP2 A = new ECP2();
FP12 r = new FP12(1);
A.copy(P);
int nb = n.nbits();
for (int i = nb - 2; i >= 1; i--)
{
lv = line(A, A, Qx, Qy);
r.smul(lv);
if (n.bit(i) == 1)
{
lv = line(A, P, Qx, Qy);
r.smul(lv);
}
r.sqr();
}
lv = line(A, A, Qx, Qy);
r.smul(lv);
/* R-ate fixup */
r.conj();
K.copy(P);
K.frob(f);
A.neg();
lv = line(A, K, Qx, Qy);
r.smul(lv);
K.frob(f);
K.neg();
lv = line(A, K, Qx, Qy);
r.smul(lv);
return(r);
}
/* reduce a DBIG to a BIG using the appropriate form of the modulus */
public static BIG mod(DBIG d)
{
BIG b;
if (ROM.MODTYPE == ROM.PSEUDO_MERSENNE)
{
long v, tw;
BIG t = d.Split(ROM.MODBITS);
b = new BIG(d);
unchecked
{
v = t.pmul((int)ROM.MConst);
}
tw = t.w[ROM.NLEN - 1];
t.w[ROM.NLEN - 1] &= ROM.TMASK;
t.w[0] += (ROM.MConst * ((tw >> ROM.TBITS) + (v << (ROM.BASEBITS - ROM.TBITS))));
b.add(t);
b.norm();
}
if (ROM.MODTYPE == ROM.MONTGOMERY_FRIENDLY)
{
for (int i = 0; i < ROM.NLEN; i++)
{
d.w[ROM.NLEN + i] += d.muladd(d.w[i], ROM.MConst - 1, d.w[i], ROM.NLEN + i - 1);
}
b = new BIG(0);
for (int i = 0; i < ROM.NLEN; i++)
{
b.w[i] = d.w[ROM.NLEN + i];
}
b.norm();
}
if (ROM.MODTYPE == ROM.NOT_SPECIAL)
{
BIG md = new BIG(ROM.Modulus);
long m, carry;
for (int i = 0; i < ROM.NLEN; i++)
{
if (ROM.MConst == -1)
{
m = (-d.w[i]) & ROM.MASK;
}
else
{
if (ROM.MConst == 1)
{
m = d.w[i];
}
else
{
m = (ROM.MConst * d.w[i]) & ROM.MASK;
}
}
carry = 0;
for (int j = 0; j < ROM.NLEN; j++)
{
carry = d.muladd(m, md.w[j], carry, i + j);
}
d.w[ROM.NLEN + i] += carry;
}
b = new BIG(0);
for (int i = 0; i < ROM.NLEN; i++)
{
b.w[i] = d.w[ROM.NLEN + i];
}
b.norm();
}
return(b);
}
