static int cswift_mod_exp_crt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *q, const BIGNUM *dmp1, const BIGNUM *dmq1,
const BIGNUM *iqmp, BN_CTX *ctx);
static int cswift_mod_exp_crt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *q, const BIGNUM *dmp1, const BIGNUM *dmq1,
const BIGNUM *iqmp, BN_CTX *ctx);