N_MONT_CTX_new(void);
 void BN_MONT_CTX_free(BN_MONT_CTX *mont);

 int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *m, BN_CTX *ctx);
 BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from);

 int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b,
                           BN_MONT_CTX *mont, BN_CTX *ctx);

 int BN_from_montgomery(BIGNUM *r, BIGNUM *a, BN_MONT_CTX *mont,
                        BN_CTX *ctx);

 int BN_to_montgomery(BIGNUM *r, BIGNUM *a, BN_MONT_CTX *mont,
                  