BN_mod_exp2_mont
int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1, const BIGNUM *p1,
if (!BN_mod_exp2_mont(t1, dsa->g, u1, dsa->pub_key, u2, dsa->p,
return BN_mod_exp2_mont(r, a, p, one, one, m, ctx, mctx);
if (!BN_mod_exp2_mont(got, a, p, b, q, m, ctx, NULL))
return BN_mod_exp2_mont(r, one, one, a, p, m, ctx, mctx);
if (BN_mod_exp2_mont(NULL, NULL, NULL, NULL, NULL, m, NULL, NULL)) {