/*

 * Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#ifndef OSSL_CRYPTO_BN_H

# define OSSL_CRYPTO_BN_H

# include <openssl/bn.h>

# include <limits.h>

BIGNUM *bn_wexpand(BIGNUM *a, int words);

BIGNUM *bn_expand2(BIGNUM *a, int words);

void bn_correct_top(BIGNUM *a);

/*

 * Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.

 * This is an array r[] of values that are either zero or odd with an

 * absolute value less than 2^w satisfying scalar = \sum_j r[j]*2^j where at

 * most one of any w+1 consecutive digits is non-zero with the exception that

 * the most significant digit may be only w-1 zeros away from that next

 * non-zero digit.

 */

signed char *bn_compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len);

int bn_get_top(const BIGNUM *a);

int bn_get_dmax(const BIGNUM *a);

/* Set all words to zero */

void bn_set_all_zero(BIGNUM *a);

/*

 * Copy the internal BIGNUM words into out which holds size elements (and size

 * must be bigger than top)

 */

int bn_copy_words(BN_ULONG *out, const BIGNUM *in, int size);

BN_ULONG *bn_get_words(const BIGNUM *a);

/*

 * Set the internal data words in a to point to words which contains size

 * elements. The BN_FLG_STATIC_DATA flag is set

 */

void bn_set_static_words(BIGNUM *a, const BN_ULONG *words, int size);

/*

 * Copy words into the BIGNUM |a|, reallocating space as necessary.

 * The negative flag of |a| is not modified.

 * Returns 1 on success and 0 on failure.

 */

/*

 * |num_words| is int because bn_expand2 takes an int. This is an internal

 * function so we simply trust callers not to pass negative values.

 */

int bn_set_words(BIGNUM *a, const BN_ULONG *words, int num_words);

/*

 * Some BIGNUM functions assume most significant limb to be non-zero, which

 * is customarily arranged by bn_correct_top. Output from below functions

 * is not processed with bn_correct_top, and for this reason it may not be

 * returned out of public API. It may only be passed internally into other

 * functions known to support non-minimal or zero-padded BIGNUMs. Even

 * though the goal is to facilitate constant-time-ness, not each subroutine

 * is constant-time by itself. They all have pre-conditions, consult source

 * code...

 */

int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,

                          BN_MONT_CTX *mont, BN_CTX *ctx);

int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,

                         BN_CTX *ctx);

int bn_from_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,

                           BN_CTX *ctx);

int bn_mod_add_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,

                         const BIGNUM *m);

int bn_mod_sub_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,

                         const BIGNUM *m);

int bn_mul_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);

int bn_sqr_fixed_top(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx);

int bn_lshift_fixed_top(BIGNUM *r, const BIGNUM *a, int n);

int bn_rshift_fixed_top(BIGNUM *r, const BIGNUM *a, int n);

int bn_div_fixed_top(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,

                     const BIGNUM *d, BN_CTX *ctx);

#define BN_PRIMETEST_COMPOSITE                    0

#define BN_PRIMETEST_COMPOSITE_WITH_FACTOR        1

#define BN_PRIMETEST_COMPOSITE_NOT_POWER_OF_PRIME 2

#define BN_PRIMETEST_PROBABLY_PRIME               3

int bn_miller_rabin_is_prime(const BIGNUM *w, int iterations, BN_CTX *ctx,

                             BN_GENCB *cb, int enhanced, int *status);

const BIGNUM *bn_get0_small_factors(void);

int bn_rsa_fips186_4_prime_MR_min_checks(int nbits);

int bn_rsa_fips186_4_gen_prob_primes(BIGNUM *p, BIGNUM *Xpout,

                                     BIGNUM *p1, BIGNUM *p2,

                                     const BIGNUM *Xp, const BIGNUM *Xp1,

                                     const BIGNUM *Xp2, int nlen,

                                     const BIGNUM *e, BN_CTX *ctx,

                                     BN_GENCB *cb);

int bn_rsa_fips186_4_derive_prime(BIGNUM *Y, BIGNUM *X, const BIGNUM *Xin,

                                  const BIGNUM *r1, const BIGNUM *r2, int nlen,

                                  const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb);

OPENSSL_CTX *bn_get_lib_ctx(BN_CTX *ctx);

extern const BIGNUM bn_inv_sqrt_2;

#endif