ZZn6 shuffle(ZZn3 &first, ZZn3 &second)
{ // shuffle from a pair ZZn3's to three ZZn2's, as required by ZZn6
ZZn6 w;
ZZn x0,x1,x2,x3,x4,x5;
ZZn2 t0,t1,t2;
first.get(x0,x2,x4);
second.get(x1,x3,x5);
t0.set(x0,x3);
t1.set(x1,x4);
t2.set(x2,x5);
w.set(t0,t1,t2);
return w;
}
ZZn6 line(ECn& A,ECn& C,ZZn& slope,ZZn3& Qx,ZZn3& Qy)
{
ZZn6 w;
ZZn3 nn=Qx;
ZZn x,y,z,t;
extract(A,x,y,z);
x*=z; t=z; z*=z; z*=t;
x*=slope; t=slope*z;
nn*=t; nn-=x; t=z;
extract(C,x,x,z);
nn+=(z*y); t*=z;
w.set(nn,-Qy*t);
return w;
}
