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boringssl/crypto/bn/bn.h
Adam Langley 5d17dd64cc Very minor BN fixes. 
Fixes one comment that mentioned the wrong function name. Also causes
two BN random functions to fail when the output is NULL. Previously they
would silently do nothing.

Change-Id: I89796ab855ea32787765c301a478352287e61190
2014-06-30 14:22:32 -07:00

816 lines
34 KiB
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/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
/* ====================================================================
* Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
/* ====================================================================
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
*
* Portions of the attached software ("Contribution") are developed by
* SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
*
* The Contribution is licensed pursuant to the Eric Young open source
* license provided above.
*
* The binary polynomial arithmetic software is originally written by
* Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
* Laboratories. */
#ifndef OPENSSL_HEADER_BN_H
#define OPENSSL_HEADER_BN_H
#include <openssl/base.h>
#include <stdio.h> /* for FILE* */
#if defined(__cplusplus)
extern "C" {
#endif
/* BN provides support for working with arbitary sized integers. For example,
* although the largest integer supported by the compiler might be 64 bits, BN
* will allow you to work with numbers until you run out of memory. */
/* BN_ULONG is the native word size when working with big integers. */
#if defined(OPENSSL_64_BIT)
#define BN_ULONG uint64_t
#define BN_BITS2 64
#elif defined(OPENSSL_32_BIT)
#define BN_ULONG uint32_t
#define BN_BITS2 32
#else
#error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
#endif
/* Allocation and freeing. */
/* BN_new creates a new, allocated BIGNUM and initialises it. */
BIGNUM *BN_new(void);
/* BN_init initialises a stack allocated |BIGNUM|. */
void BN_init(BIGNUM *bn);
/* BN_free frees the data referenced by |bn| and, if |bn| was originally
* allocated on the heap, frees |bn| also. */
void BN_free(BIGNUM *bn);
/* BN_clear_free erases and frees the data referenced by |bn| and, if |bn| was
* originally allocated on the heap, frees |bn| also. */
void BN_clear_free(BIGNUM *bn);
/* BN_dup allocates a new BIGNUM and sets it equal to |src|. It returns the
* allocated BIGNUM on success or NULL otherwise. */
BIGNUM *BN_dup(const BIGNUM *src);
/* BN_copy sets |dest| equal to |src| and returns |dest|. */
BIGNUM *BN_copy(BIGNUM *dest, const BIGNUM *src);
/* BN_clear sets |bn| to zero and erases the old data. */
void BN_clear(BIGNUM *bn);
/* BN_value_one returns a static BIGNUM with value 1. */
const BIGNUM *BN_value_one(void);
/* BN_with_flags initialises a stack allocated |BIGNUM| with pointers to the
* contents of |in| but with |flags| ORed into the flags field.
*
* Note: the two BIGNUMs share state and so |out| should /not/ be passed to
* |BN_free|. */
void BN_with_flags(BIGNUM *out, const BIGNUM *in, int flags);
/* Basic functions. */
/* BN_num_bits returns the minimum number of bits needed to represent the
* absolute value of |bn|. */
unsigned BN_num_bits(const BIGNUM *bn);
/* BN_num_bytes returns the minimum number of bytes needed to represent the
* absolute value of |bn|. */
unsigned BN_num_bytes(const BIGNUM *bn);
/* BN_zero sets |bn| to zero. */
void BN_zero(BIGNUM *bn);
/* BN_one sets |bn| to one. It returns one on success or zero on allocation
* failure. */
int BN_one(BIGNUM *bn);
/* BN_set_word sets |bn| to |value|. It returns one on success or zero on
* allocation failure. */
int BN_set_word(BIGNUM *bn, BN_ULONG value);
/* BN_set_negative sets the sign of |bn|. */
void BN_set_negative(BIGNUM *bn, int sign);
/* BN_is_negative returns one if |bn| is negative and zero otherwise. */
int BN_is_negative(const BIGNUM *bn);
/* BN_get_flags returns |bn->flags| & |flags|. */
int BN_get_flags(const BIGNUM *bn, int flags);
/* BN_set_flags sets |flags| on |bn|. */
void BN_set_flags(BIGNUM *bn, int flags);
/* Conversion functions. */
/* BN_bin2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
* a big-endian number, and returns |ret|. If |ret| is NULL then a fresh
* |BIGNUM| is allocated and returned. It returns NULL on allocation
* failure. */
BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret);
/* BN_bn2bin serialises the absolute value of |in| to |out| as a big-endian
* integer, which must have |BN_num_bytes| of space available. It returns the
* number of bytes written. */
size_t BN_bn2bin(const BIGNUM *in, uint8_t *out);
/* BN_bn2bin_padded serialises the absolute value of |in| to |out| as a
* big-endian integer. The integer is padded with leading zeros up to size
* |len|. If |len| is smaller than |BN_num_bytes|, the function fails and
* returns 0. Otherwise, it returns 1. */
int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in);
/* BN_bn2hex returns an allocated string that contains a NUL-terminated, hex
* representation of |bn|. If |bn| is negative, the first char in the resulting
* string will be '-'. Returns NULL on allocation failure. */
char *BN_bn2hex(const BIGNUM *bn);
/* BN_hex2bn parses the leading hex number from |in|, which may be proceeded by
* a '-' to indicate a negative number and may contain trailing, non-hex data.
* If |outp| is not NULL, it constructs a BIGNUM equal to the hex number and
* stores it in |*outp|. If |*outp| is NULL then it allocates a new BIGNUM and
* updates |*outp|. It returns the number of bytes of |in| processed or zero on
* error. */
int BN_hex2bn(BIGNUM **outp, const char *in);
/* BN_bn2dec returns an allocated string that contains a NUL-terminated,
* decimal representation of |bn|. If |bn| is negative, the first char in the
* resulting string will be '-'. Returns NULL on allocation failure. */
char *BN_bn2dec(const BIGNUM *a);
/* BN_dec2bn parses the leading decimal number from |in|, which may be
* proceeded by a '-' to indicate a negative number and may contain trailing,
* non-decimal data. If |outp| is not NULL, it constructs a BIGNUM equal to the
* decimal number and stores it in |*outp|. If |*outp| is NULL then it
* allocates a new BIGNUM and updates |*outp|. It returns the number of bytes
* of |in| processed or zero on error. */
int BN_dec2bn(BIGNUM **outp, const char *in);
/* BN_asc2bn acts like |BN_dec2bn| or |BN_hex2bn| depending on whether |in|
* begins with "0X" or "0x" (indicating hex) or not (indicating decimal). A
* leading '-' is still permitted and comes before the optional 0X/0x. It
* returns one on success or zero on error. */
int BN_asc2bn(BIGNUM **outp, const char *in);
/* BN_print writes a hex encoding of |a| to |bio|. It returns one on success
* and zero on error. */
int BN_print(BIO *bio, const BIGNUM *a);
/* BN_print_fp acts like |BIO_print|, but wraps |fp| in a |BIO| first. */
int BN_print_fp(FILE *fp, const BIGNUM *a);
/* BN_get_word returns the absolute value of |bn| as a single word. If |bn| is
* too large to be represented as a single word, the maximum possible value
* will be returned. */
BN_ULONG BN_get_word(const BIGNUM *bn);
/* BIGNUM pools.
*
* Certain BIGNUM operations need to use many temporary variables and
* allocating and freeing them can be quite slow. Thus such opertions typically
* take a |BN_CTX| parameter, which contains a pool of |BIGNUMs|. The |ctx|
* argument to a public function may be NULL, in which case a local |BN_CTX|
* will be created just for the lifetime of that call.
*
* A function must call |BN_CTX_start| first. Then, |BN_CTX_get| may be called
* repeatedly to obtain temporary |BIGNUM|s. All |BN_CTX_get| calls must be made
* before calling any other functions that use the |ctx| as an argument.
*
* Finally, |BN_CTX_end| must be called before returning from the function.
* When |BN_CTX_end| is called, the |BIGNUM| pointers obtained from
* |BN_CTX_get| become invalid. */
/* BN_CTX_new returns a new, empty BN_CTX or NULL on allocation failure. */
BN_CTX *BN_CTX_new(void);
/* BN_CTX_free frees all BIGNUMs contained in |ctx| and then frees |ctx|
* itself. */
void BN_CTX_free(BN_CTX *ctx);
/* BN_CTX_start "pushes" a new entry onto the |ctx| stack and allows future
* calls to |BN_CTX_get|. */
void BN_CTX_start(BN_CTX *ctx);
/* BN_CTX_get returns a new |BIGNUM|, or NULL on allocation failure. Once
* |BN_CTX_get| has returned NULL, all future calls will also return NULL until
* |BN_CTX_end| is called. */
BIGNUM *BN_CTX_get(BN_CTX *ctx);
/* BN_CTX_end invalidates all |BIGNUM|s returned from |BN_CTX_get| since the
* matching |BN_CTX_start| call. */
void BN_CTX_end(BN_CTX *ctx);
/* Simple arithmetic */
/* BN_add sets |r| = |a| + |b|, where |r| may be the same pointer as either |a|
* or |b|. It returns one on success and zero on allocation failure. */
int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_uadd sets |r| = |a| + |b|, where |a| and |b| are non-negative and |r| may
* be the same pointer as either |a| or |b|. It returns one on success and zero
* on allocation failure. */
int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_add_word adds |w| to |a|. It returns one on success and zero otherwise. */
int BN_add_word(BIGNUM *a, BN_ULONG w);
/* BN_sub sets |r| = |a| + |b|, where |r| must be a distinct pointer from |a|
* and |b|. It returns one on success and zero on allocation failure. */
int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_usub sets |r| = |a| + |b|, where |a| and |b| are non-negative integers,
* |b| < |a| and |r| must be a distinct pointer from |a| and |b|. It returns
* one on success and zero on allocation failure. */
int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_sub_word subtracts |w| from |a|. It returns one on success and zero on
* allocation failure. */
int BN_sub_word(BIGNUM *a, BN_ULONG w);
/* BN_mul sets |r| = |a| * |b|, where |r| may be the same pointer as |a| or
* |b|. Returns one on success and zero otherwise. */
int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
/* BN_mul_word sets |bn| = |bn| * |w|. It returns one on success or zero on
* allocation failure. */
int BN_mul_word(BIGNUM *bn, BN_ULONG w);
/* BN_sqr sets |r| = |a|^2 (i.e. squares), where |r| may be the same pointer as
* |a|. Returns one on success and zero otherwise. This is more efficient than
* BN_mul(r, a, a, ctx). */
int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx);
/* BN_div divides |numerator| by |divisor| and places the result in |quotient|
* and the remainder in |rem|. Either of |quotient| or |rem| may be NULL, in
* which case the respective value is not returned. The result is rounded
* towards zero; thus if |numerator| is negative, the remainder will be zero or
* negative. It returns one on success or zero on error. */
int BN_div(BIGNUM *quotient, BIGNUM *rem, const BIGNUM *numerator,
const BIGNUM *divisor, BN_CTX *ctx);
/* BN_div_word sets |numerator| = |numerator|/|divisor| and returns the
* remainder or (BN_ULONG)-1 on error. */
BN_ULONG BN_div_word(BIGNUM *numerator, BN_ULONG divisor);
/* BN_sqrt sets |*out_sqrt| (which may be the same |BIGNUM| as |in|) to the
* square root of |in|, using |ctx|. It returns one on success or zero on
* error. Negative numbers and non-square numbers will result in an error with
* appropriate errors on the error queue. */
int BN_sqrt(BIGNUM *out_sqrt, const BIGNUM *in, BN_CTX *ctx);
/* Comparison functions */
/* BN_cmp returns a value less than, equal to or greater than zero if |a| is
* less than, equal to or greater than |b|, respectively. */
int BN_cmp(const BIGNUM *a, const BIGNUM *b);
/* BN_ucmp returns a value less than, equal to or greater than zero if the
* absolute value of |a| is less than, equal to or greater than the absolute
* value of |b|, respectively. */
int BN_ucmp(const BIGNUM *a, const BIGNUM *b);
/* BN_abs_is_word returns one if the absolute value of |bn| equals |w| and zero
* otherwise. */
int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w);
/* BN_is_zero returns one if |bn| is zero and zero otherwise. */
int BN_is_zero(const BIGNUM *bn);
/* BN_is_one returns one if |bn| equals one and zero otherwise. */
int BN_is_one(const BIGNUM *bn);
/* BN_is_word returns one if |bn| is exactly |w| and zero otherwise. */
int BN_is_word(const BIGNUM *bn, BN_ULONG w);
/* BN_is_odd returns one if |bn| is odd and zero otherwise. */
int BN_is_odd(const BIGNUM *bn);
/* Bitwise operations. */
/* BN_lshift sets |r| equal to |a| << n. The |a| and |r| arguments may be the
* same |BIGNUM|. It returns one on success and zero on allocation failure. */
int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
/* BN_lshift1 sets |r| equal to |a| << 1, where |r| and |a| may be the same
* pointer. It returns one on success and zero on allocation failure. */
int BN_lshift1(BIGNUM *r, const BIGNUM *a);
/* BN_rshift sets |r| equal to |a| >> n, where |r| and |a| may be the same
* pointer. It returns one on success and zero on allocation failure. */
int BN_rshift(BIGNUM *r, const BIGNUM *a, int n);
/* BN_rshift1 sets |r| equal to |a| >> 1, where |r| and |a| may be the same
* pointer. It returns one on success and zero on allocation failure. */
int BN_rshift1(BIGNUM *r, const BIGNUM *a);
/* BN_set_bit sets the |n|th, least-significant bit in |a|. For example, if |a|
* is 2 then setting bit zero will make it 3. It returns one on success or zero
* on allocation failure. */
int BN_set_bit(BIGNUM *a, int n);
/* BN_clear_bit clears the |n|th, least-significant bit in |a|. For example, if
* |a| is 3, clearing bit zero will make it two. It returns one on success or
* zero on allocation failure. */
int BN_clear_bit(BIGNUM *a, int n);
/* BN_is_bit_set returns the value of the |n|th, least-significant bit in |a|,
* or zero if the bit doesn't exist. */
int BN_is_bit_set(const BIGNUM *a, int n);
/* BN_mask_bits truncates |a| so that it is only |n| bits long. It returns one
* on success or zero if |n| is greater than the length of |a| already. */
int BN_mask_bits(BIGNUM *a, int n);
/* Modulo arithmetic. */
/* BN_mod_word returns |a| mod |w|. */
BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
/* BN_mod is a helper macro that calls |BN_div| and discards the quotient. */
#define BN_mod(rem, numerator, divisor, ctx) \
BN_div(NULL, (rem), (numerator), (divisor), (ctx))
/* BN_nnmod is a non-negative modulo function. It acts like |BN_mod|, but 0 <=
* |rem| < |divisor| is always true. */
int BN_nnmod(BIGNUM *rem, const BIGNUM *numerator, const BIGNUM *divisor,
BN_CTX *ctx);
/* BN_mod_add sets |r| = |a| + |b| mod |m|. It returns one on success and zero
* on error. */
int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
BN_CTX *ctx);
/* BN_mod_add_quick acts like |BN_mod_add| but requires that |a| and |b| be
* non-negative and less than |m|. */
int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m);
/* BN_mod_sub sets |r| = |a| - |b| mod |m|. It returns one on success and zero
* on error. */
int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
BN_CTX *ctx);
/* BN_mod_sub_quick acts like |BN_mod_sub| but requires that |a| and |b| be
* non-negative and less than |m|. */
int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m);
/* BN_mod_mul sets |r| = |a|*|b| mod |m|. It returns one on success and zero
* on error. */
int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
BN_CTX *ctx);
/* BN_mod_mul sets |r| = |a|^2 mod |m|. It returns one on success and zero
* on error. */
int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx);
/* BN_mod_lshift sets |r| = (|a| << n) mod |m|, where |r| and |a| may be the
* same pointer. It returns one on success and zero on error. */
int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m,
BN_CTX *ctx);
/* BN_mod_lshift_quick acts like |BN_mod_lshift| but requires that |a| be
* non-negative and less than |m|. */
int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m);
/* BN_mod_lshift1 sets |r| = (|a| << 1) mod |m|, where |r| and |a| may be the
* same pointer. It returns one on success and zero on error. */
int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx);
/* BN_mod_lshift1_quick acts like |BN_mod_lshift1| but requires that |a| be
* non-negative and less than |m|. */
int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *m);
/* BN_mod_sqrt returns a |BIGNUM|, r, such that r^2 == a (mod p). */
BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx);
/* Random and prime number generation. */
/* BN_rand sets |rnd| to a random number of length |bits|. If |top| is zero,
* the most-significant bit will be set. If |top| is one, the two most
* significant bits will be set.
*
* If |top| is -1 then no extra action will be taken and |BN_num_bits(rnd)| may
* not equal |bits| if the most significant bits randomly ended up as zeros.
*
* If |bottom| is non-zero, the least-significant bit will be set. The function
* returns one on success or zero otherwise. */
int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
/* BN_pseudo_rand is an alias for |BN_rand|. */
int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
/* BN_rand_range sets |rnd| to a random value [0..range). It returns one on
* success and zero otherwise. */
int BN_rand_range(BIGNUM *rnd, const BIGNUM *range);
/* BN_pseudo_rand_range is an alias for BN_rand_range. */
int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range);
/* BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike
* BN_rand_range, it also includes the contents of |priv| and |message| in the
* generation so that an RNG failure isn't fatal as long as |priv| remains
* secret. This is intended for use in DSA and ECDSA where an RNG weakness
* leads directly to private key exposure unless this function is used.
* It returns one on success and zero on error. */
int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv,
const uint8_t *message, size_t message_len,
BN_CTX *ctx);
/* BN_GENCB holds a callback function that is used by generation functions that
* can take a very long time to complete. Use |BN_GENCB_set| to initialise a
* |BN_GENCB| structure.
*
* The callback receives the address of that |BN_GENCB| structure as its last
* argument and the user is free to put an arbitary pointer in |arg|. The other
* arguments are set as follows:
* event=BN_GENCB_GENERATED, n=i: after generating the i'th possible prime
* number.
* event=BN_GENCB_PRIME_TEST, n=-1: when finished trial division primality
* checks.
* event=BN_GENCB_PRIME_TEST, n=i: when the i'th primality test has finished.
*
* The callback can return zero to abort the generation progress or one to
* allow it to continue.
*
* When other code needs to call a BN generation function it will often take a
* BN_GENCB argument and may call the function with other argument values. */
#define BN_GENCB_GENERATED 0
#define BN_GENCB_PRIME_TEST 1
struct bn_gencb_st {
void *arg; /* callback-specific data */
int (*callback)(int event, int n, struct bn_gencb_st *);
};
/* BN_GENCB_set configures |callback| to call |f| and sets |callout->arg| to
* |arg|. */
void BN_GENCB_set(BN_GENCB *callback,
int (*f)(int event, int n, struct bn_gencb_st *),
void *arg);
/* BN_GENCB_call calls |callback|, if not NULL, and returns the return value of
* the callback, or 1 if |callback| is NULL. */
int BN_GENCB_call(BN_GENCB *callback, int event, int n);
/* BN_generate_prime_ex sets |ret| to a prime number of |bits| length. If safe
* is non-zero then the prime will be such that (ret-1)/2 is also a prime.
* (This is needed for Diffie-Hellman groups to ensure that the only subgroups
* are of size 2 and (p-1)/2.).
*
* If |add| is not NULL, the prime will fulfill the condition |ret| % |add| ==
* |rem| in order to suit a given generator. (If |rem| is NULL then |ret| %
* |add| == 1.)
*
* If |cb| is not NULL, it will be called during processing to give an
* indication of progress. See the comments for |BN_GENCB|. It returns one on
* success and zero otherwise. */
int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, const BIGNUM *add,
const BIGNUM *rem, BN_GENCB *cb);
/* BN_prime_checks is magic value that can be used as the |checks| argument to
* the primality testing functions in order to automatically select a number of
* Miller-Rabin checks that gives a false positive rate of ~2^{-80}. */
#define BN_prime_checks 0
/* BN_primality_test sets |*is_probably_prime| to one if |candidate| is
* probably a prime number by the Miller-Rabin test or zero if it's certainly
* not.
*
* If |do_trial_division| is non-zero then |candidate| will be tested against a
* list of small primes before Miller-Rabin tests. The probability of this
* function returning a false positive is 2^{2*checks}. If |checks| is
* |BN_prime_checks| then a value that results in approximately 2^{-80} false
* positive probability is used. If |cb| is not NULL then it is called during
* the checking process. See the comment above |BN_GENCB|.
*
* The function returns one on success and zero on error.
*
* (If you are unsure whether you want |do_trial_division|, don't set it.) */
int BN_primality_test(int *is_probably_prime, const BIGNUM *candidate,
int checks, BN_CTX *ctx, int do_trial_division,
BN_GENCB *cb);
/* BN_is_prime_fasttest_ex returns one if |candidate| is probably a prime
* number by the Miller-Rabin test, zero if it's certainly not and -1 on error.
*
* If |do_trial_division| is non-zero then |candidate| will be tested against a
* list of small primes before Miller-Rabin tests. The probability of this
* function returning one when |candidate| is composite is 2^{2*checks}. If
* |checks| is |BN_prime_checks| then a value that results in approximately
* 2^{-80} false positive probability is used. If |cb| is not NULL then it is
* called during the checking process. See the comment above |BN_GENCB|.
*
* WARNING: deprecated. Use |BN_primality_test|. */
int BN_is_prime_fasttest_ex(const BIGNUM *candidate, int checks, BN_CTX *ctx,
int do_trial_division, BN_GENCB *cb);
/* BN_is_prime_ex acts the same as |BN_is_prime_fasttest_ex| with
* |do_trial_division| set to zero.
*
* WARNING: deprecated: Use |BN_primality_test|. */
int BN_is_prime_ex(const BIGNUM *candidate, int checks, BN_CTX *ctx,
BN_GENCB *cb);
/* Number theory functions */
/* BN_gcd sets |r| = gcd(|a|, |b|). It returns one on success and zero
* otherwise. */
int BN_gcd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
/* BN_mod_inverse sets |out| equal to |a|^-1, mod |n|. If either of |a| or |n|
* have |BN_FLG_CONSTTIME| set then the operation is performed in constant
* time. If |out| is NULL, a fresh BIGNUM is allocated. It returns the result
* or NULL on error. */
BIGNUM *BN_mod_inverse(BIGNUM *out, const BIGNUM *a, const BIGNUM *n,
BN_CTX *ctx);
/* BN_kronecker returns the Kronecker symbol of |a| and |b| (which is -1, 0 or
* 1), or -2 on error. */
int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
/* Montgomery arithmetic. */
/* BN_MONT_CTX contains the precomputed values needed to work in a specific
* Montgomery domain. */
/* BN_MONT_CTX_new returns a fresh BN_MONT_CTX or NULL on allocation failure. */
BN_MONT_CTX *BN_MONT_CTX_new(void);
/* BN_MONT_CTX_init initialises a stack allocated |BN_MONT_CTX|. */
void BN_MONT_CTX_init(BN_MONT_CTX *mont);
/* BN_MONT_CTX_free frees the contexts of |mont| and, if it was originally
* allocated with |BN_MONT_CTX_new|, |mont| itself. */
void BN_MONT_CTX_free(BN_MONT_CTX *mont);
/* BN_MONT_CTX_copy sets |to| equal to |from|. It returns |to| on success or
* NULL on error. */
BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from);
/* BN_MONT_CTX_set sets up a Montgomery context given the modulus, |mod|. It
* returns one on success and zero on error. */
int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx);
/* BN_MONT_CTX_set_locked takes the lock indicated by |lock| and checks whether
* |*pmont| is NULL. If so, it creates a new |BN_MONT_CTX| and sets the modulus
* for it to |mod|. It then stores it as |*pmont| and returns it, or NULL on
* error.
*
* If |*pmont| is already non-NULL then the existing value is returned. */
BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock,
const BIGNUM *mod, BN_CTX *ctx);
/* BN_to_montgomery sets |ret| equal to |a| in the Montgomery domain. It
* returns one on success and zero on error. */
int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a, const BN_MONT_CTX *mont,
BN_CTX *ctx);
/* BN_from_montgomery sets |ret| equal to |a| * R^-1, i.e. translates values
* out of the Montgomery domain. It returns one on success or zero on error. */
int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, const BN_MONT_CTX *mont,
BN_CTX *ctx);
/* BN_mod_mul_montgomery set |r| equal to |a| * |b|, in the Montgomery domain.
* Both |a| and |b| must already be in the Montgomery domain (by
* |BN_to_montgomery|). It returns one on success or zero on error. */
int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BN_MONT_CTX *mont, BN_CTX *ctx);
/* Exponentiation. */
/* BN_exp sets |r| equal to |a|^{|p|}. It does so with a square-and-multiply
* algorithm that leaks side-channel information. It returns one on success or
* zero otherwise. */
int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx);
/* BN_mod_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
* algorithm for the values provided and can run in constant time if
* |BN_FLG_CONSTTIME| is set for |p|. It returns one on success or zero
* otherwise. */
int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
BN_CTX *ctx);
int BN_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx,
BN_MONT_CTX *in_mont);
int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1, const BIGNUM *p1,
const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
BN_CTX *ctx, BN_MONT_CTX *m_ctx);
/* Private functions */
struct bignum_st {
BN_ULONG *d; /* Pointer to an array of 'BN_BITS2' bit chunks in little-endian
order. */
int top; /* Index of last used element in |d|, plus one. */
int dmax; /* Size of |d|, in words. */
int neg; /* one if the number is negative */
int flags; /* bitmask of BN_FLG_* values */
};
struct bn_mont_ctx_st {
BIGNUM RR; /* used to convert to montgomery form */
BIGNUM N; /* The modulus */
BIGNUM Ni; /* R*(1/R mod N) - N*Ni = 1
* (Ni is only stored for bignum algorithm) */
BN_ULONG n0[2]; /* least significant word(s) of Ni;
(type changed with 0.9.9, was "BN_ULONG n0;" before) */
int flags;
int ri; /* number of bits in R */
};
unsigned BN_num_bits_word(BN_ULONG l);
#define BN_FLG_MALLOCED 0x01
#define BN_FLG_STATIC_DATA 0x02
/* avoid leaking exponent information through timing, BN_mod_exp_mont() will
* call BN_mod_exp_mont_consttime, BN_div() will call BN_div_no_branch,
* BN_mod_inverse() will call BN_mod_inverse_no_branch. */
#define BN_FLG_CONSTTIME 0x04
#if defined(__cplusplus)
} /* extern C */
#endif
#define BN_F_BN_bn2hex 100
#define BN_F_BN_new 101
#define BN_F_BN_exp 102
#define BN_F_mod_exp_recp 103
#define BN_F_BN_mod_sqrt 104
#define BN_F_BN_rand 105
#define BN_F_BN_rand_range 106
#define BN_F_bn_wexpand 107
#define BN_F_BN_mod_exp_mont 108
#define BN_F_BN_mod_exp2_mont 109
#define BN_F_BN_CTX_get 110
#define BN_F_BN_mod_inverse 111
#define BN_F_BN_bn2dec 112
#define BN_F_BN_div 113
#define BN_F_BN_div_recp 114
#define BN_F_BN_mod_exp_mont_consttime 115
#define BN_F_BN_mod_exp_mont_word 116
#define BN_F_BN_CTX_start 117
#define BN_F_BN_usub 118
#define BN_F_BN_mod_lshift_quick 119
#define BN_F_BN_CTX_new 120
#define BN_F_BN_mod_inverse_no_branch 121
#define BN_F_BN_generate_dsa_nonce 122
#define BN_F_BN_generate_prime_ex 123
#define BN_F_BN_sqrt 124
#define BN_R_NOT_A_SQUARE 100
#define BN_R_TOO_MANY_ITERATIONS 101
#define BN_R_INPUT_NOT_REDUCED 102
#define BN_R_TOO_MANY_TEMPORARY_VARIABLES 103
#define BN_R_NO_INVERSE 104
#define BN_R_NOT_INITIALIZED 105
#define BN_R_DIV_BY_ZERO 106
#define BN_R_CALLED_WITH_EVEN_MODULUS 107
#define BN_R_EXPAND_ON_STATIC_BIGNUM_DATA 108
#define BN_R_BAD_RECIPROCAL 109
#define BN_R_P_IS_NOT_PRIME 110
#define BN_R_INVALID_RANGE 111
#define BN_R_ARG2_LT_ARG3 112
#define BN_R_BIGNUM_TOO_LONG 113
#define BN_R_PRIVATE_KEY_TOO_LARGE 114
#define BN_R_BITS_TOO_SMALL 115
#define BN_R_NEGATIVE_NUMBER 116
#endif /* OPENSSL_HEADER_BN_H */
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