BN_gcd_ct
int BN_gcd_ct(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
r = BN_gcd_ct(m, i, j, ctx);
if (!BN_gcd_ct(r1, r2, rsa->e, ctx))
if (!BN_gcd_ct(r1, r2, rsa->e, ctx))
int BN_gcd_ct(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
.fn = BN_gcd_ct,