/* Multiply P by e in group G1 */
public static ECP G1mul(ECP P, BIG e)
{
ECP R;
if (ROM.USE_GLV)
{
P.affine();
R = new ECP();
R.copy(P);
int i, np, nn;
ECP Q = new ECP();
Q.copy(P);
BIG q = new BIG(ROM.CURVE_Order);
FP cru = new FP(new BIG(ROM.CURVE_Cru));
BIG t = new BIG(0);
BIG[] u = glv(e);
Q.getx().mul(cru);
np = u[0].nbits();
t.copy(BIG.modneg(u[0], q));
nn = t.nbits();
if (nn < np)
{
u[0].copy(t);
R.neg();
}
np = u[1].nbits();
t.copy(BIG.modneg(u[1], q));
nn = t.nbits();
if (nn < np)
{
u[1].copy(t);
Q.neg();
}
R = R.mul2(u[0], Q, u[1]);
}
else
{
R = P.mul(e);
}
return(R);
}
/* Constant time select from pre-computed table */
private void select(ECP[] W, int b)
{
ECP MP = new ECP();
int m = b >> 31;
int babs = (b ^ m) - m;
babs = (babs - 1) / 2;
cmove(W[0], teq(babs, 0)); // conditional move
cmove(W[1], teq(babs, 1));
cmove(W[2], teq(babs, 2));
cmove(W[3], teq(babs, 3));
cmove(W[4], teq(babs, 4));
cmove(W[5], teq(babs, 5));
cmove(W[6], teq(babs, 6));
cmove(W[7], teq(babs, 7));
MP.copy(this);
MP.neg();
cmove(MP, (int)(m & 1));
}
/* this-=Q */
public void sub(ECP Q)
{
Q.neg();
add(Q);
Q.neg();
}
