/* Extract Server Secret SST=S*Q where Q is fixed generator in G2 and S is master secret */
public static int GET_SERVER_SECRET(sbyte[] S, sbyte[] SST)
{
ECP2 Q = new ECP2(new FP2(new BIG(ROM.CURVE_Pxa), new BIG(ROM.CURVE_Pxb)), new FP2(new BIG(ROM.CURVE_Pya), new BIG(ROM.CURVE_Pyb)));
BIG s = BIG.fromBytes(S);
Q = PAIR.G2mul(Q, s);
Q.toBytes(SST);
return(0);
}
/* W=W1+W2 in group G2 */
public static int RECOMBINE_G2(sbyte[] W1, sbyte[] W2, sbyte[] W)
{
ECP2 P = ECP2.fromBytes(W1);
ECP2 Q = ECP2.fromBytes(W2);
if (P.is_infinity() || Q.is_infinity())
{
return(INVALID_POINT);
}
P.add(Q);
P.toBytes(W);
return(0);
}