/* RSA decryption with the private key */
public static void DECRYPT(rsa_private_key PRIV, sbyte[] G, sbyte[] F)
{
int n = PRIV.p.getlen();
FF g = new FF(2 * n);
FF.fromBytes(g, G);
FF jp = g.dmod(PRIV.p);
FF jq = g.dmod(PRIV.q);
jp.skpow(PRIV.dp, PRIV.p);
jq.skpow(PRIV.dq, PRIV.q);
g.zero();
g.dscopy(jp);
jp.mod(PRIV.q);
if (FF.comp(jp, jq) > 0)
{
jq.add(PRIV.q);
}
jq.sub(jp);
jq.norm();
FF t = FF.mul(PRIV.c, jq);
jq = t.dmod(PRIV.q);
t = FF.mul(jq, PRIV.p);
g.add(t);
g.norm();
g.toBytes(F);
}
/* nresidue mod m */
public void nres(FF m)
{
int n = m.length;
FF d = new FF(2 * n);
d.dsucopy(this);
copy(d.dmod(m));
}
/* generate random x */
public void randomnum(FF p, RAND rng)
{
int n = length;
FF d = new FF(2 * n);
for (int i = 0; i < 2 * n; i++)
{
d.v[i].copy(BIG.random(rng));
}
copy(d.dmod(p));
}