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Adam Langley95c29f32014-06-20 12:00:00 -07001/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.]
56 */
57/* ====================================================================
58 * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
59 *
60 * Redistribution and use in source and binary forms, with or without
61 * modification, are permitted provided that the following conditions
62 * are met:
63 *
64 * 1. Redistributions of source code must retain the above copyright
65 * notice, this list of conditions and the following disclaimer.
66 *
67 * 2. Redistributions in binary form must reproduce the above copyright
68 * notice, this list of conditions and the following disclaimer in
69 * the documentation and/or other materials provided with the
70 * distribution.
71 *
72 * 3. All advertising materials mentioning features or use of this
73 * software must display the following acknowledgment:
74 * "This product includes software developed by the OpenSSL Project
75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76 *
77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78 * endorse or promote products derived from this software without
79 * prior written permission. For written permission, please contact
80 * openssl-core@openssl.org.
81 *
82 * 5. Products derived from this software may not be called "OpenSSL"
83 * nor may "OpenSSL" appear in their names without prior written
84 * permission of the OpenSSL Project.
85 *
86 * 6. Redistributions of any form whatsoever must retain the following
87 * acknowledgment:
88 * "This product includes software developed by the OpenSSL Project
89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90 *
91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102 * OF THE POSSIBILITY OF SUCH DAMAGE.
103 * ====================================================================
104 *
105 * This product includes cryptographic software written by Eric Young
106 * (eay@cryptsoft.com). This product includes software written by Tim
107 * Hudson (tjh@cryptsoft.com).
108 *
109 */
110/* ====================================================================
111 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
112 *
113 * Portions of the attached software ("Contribution") are developed by
114 * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
115 *
116 * The Contribution is licensed pursuant to the Eric Young open source
117 * license provided above.
118 *
119 * The binary polynomial arithmetic software is originally written by
120 * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
121 * Laboratories. */
122
123#ifndef OPENSSL_HEADER_BN_H
124#define OPENSSL_HEADER_BN_H
125
126#include <openssl/base.h>
Adam Langley683d7bd2015-04-13 11:04:14 -0700127#include <openssl/thread.h>
Adam Langley95c29f32014-06-20 12:00:00 -0700128
Matt Braithwaitee7b32c32015-04-30 13:02:30 -0700129#include <inttypes.h> /* for PRIu64 and friends */
Adam Langley95c29f32014-06-20 12:00:00 -0700130#include <stdio.h> /* for FILE* */
131
132#if defined(__cplusplus)
133extern "C" {
134#endif
135
136
137/* BN provides support for working with arbitary sized integers. For example,
138 * although the largest integer supported by the compiler might be 64 bits, BN
139 * will allow you to work with numbers until you run out of memory. */
140
141
David Benjaminc561aa62015-05-09 01:38:06 -0400142/* BN_ULONG is the native word size when working with big integers.
143 *
144 * Note: on some platforms, inttypes.h does not define print format macros in
145 * C++ unless |__STDC_FORMAT_MACROS| defined. As this is a public header, bn.h
146 * does not define |__STDC_FORMAT_MACROS| itself. C++ source files which use the
147 * FMT macros must define it externally. */
Adam Langley95c29f32014-06-20 12:00:00 -0700148#if defined(OPENSSL_64_BIT)
149#define BN_ULONG uint64_t
150#define BN_BITS2 64
David Benjamin4a9313a2016-10-24 20:02:26 -0400151#define BN_DEC_FMT1 "%" PRIu64
152#define BN_DEC_FMT2 "%019" PRIu64
153#define BN_HEX_FMT1 "%" PRIx64
154#define BN_HEX_FMT2 "%016" PRIx64
Adam Langley95c29f32014-06-20 12:00:00 -0700155#elif defined(OPENSSL_32_BIT)
156#define BN_ULONG uint32_t
157#define BN_BITS2 32
David Benjamin4a9313a2016-10-24 20:02:26 -0400158#define BN_DEC_FMT1 "%" PRIu32
159#define BN_DEC_FMT2 "%09" PRIu32
160#define BN_HEX_FMT1 "%" PRIx32
161#define BN_HEX_FMT2 "%08" PRIx64
Adam Langley95c29f32014-06-20 12:00:00 -0700162#else
163#error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
164#endif
165
166
167/* Allocation and freeing. */
168
169/* BN_new creates a new, allocated BIGNUM and initialises it. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700170OPENSSL_EXPORT BIGNUM *BN_new(void);
Adam Langley95c29f32014-06-20 12:00:00 -0700171
172/* BN_init initialises a stack allocated |BIGNUM|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700173OPENSSL_EXPORT void BN_init(BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700174
175/* BN_free frees the data referenced by |bn| and, if |bn| was originally
176 * allocated on the heap, frees |bn| also. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700177OPENSSL_EXPORT void BN_free(BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700178
179/* BN_clear_free erases and frees the data referenced by |bn| and, if |bn| was
180 * originally allocated on the heap, frees |bn| also. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700181OPENSSL_EXPORT void BN_clear_free(BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700182
183/* BN_dup allocates a new BIGNUM and sets it equal to |src|. It returns the
184 * allocated BIGNUM on success or NULL otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700185OPENSSL_EXPORT BIGNUM *BN_dup(const BIGNUM *src);
Adam Langley95c29f32014-06-20 12:00:00 -0700186
David Benjamin1c703cb2015-06-11 21:42:14 -0400187/* BN_copy sets |dest| equal to |src| and returns |dest| or NULL on allocation
188 * failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700189OPENSSL_EXPORT BIGNUM *BN_copy(BIGNUM *dest, const BIGNUM *src);
Adam Langley95c29f32014-06-20 12:00:00 -0700190
191/* BN_clear sets |bn| to zero and erases the old data. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700192OPENSSL_EXPORT void BN_clear(BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700193
194/* BN_value_one returns a static BIGNUM with value 1. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700195OPENSSL_EXPORT const BIGNUM *BN_value_one(void);
Adam Langley95c29f32014-06-20 12:00:00 -0700196
197/* BN_with_flags initialises a stack allocated |BIGNUM| with pointers to the
198 * contents of |in| but with |flags| ORed into the flags field.
199 *
200 * Note: the two BIGNUMs share state and so |out| should /not/ be passed to
201 * |BN_free|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700202OPENSSL_EXPORT void BN_with_flags(BIGNUM *out, const BIGNUM *in, int flags);
Adam Langley95c29f32014-06-20 12:00:00 -0700203
204
205/* Basic functions. */
206
207/* BN_num_bits returns the minimum number of bits needed to represent the
208 * absolute value of |bn|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700209OPENSSL_EXPORT unsigned BN_num_bits(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700210
211/* BN_num_bytes returns the minimum number of bytes needed to represent the
212 * absolute value of |bn|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700213OPENSSL_EXPORT unsigned BN_num_bytes(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700214
215/* BN_zero sets |bn| to zero. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700216OPENSSL_EXPORT void BN_zero(BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700217
218/* BN_one sets |bn| to one. It returns one on success or zero on allocation
219 * failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700220OPENSSL_EXPORT int BN_one(BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700221
222/* BN_set_word sets |bn| to |value|. It returns one on success or zero on
223 * allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700224OPENSSL_EXPORT int BN_set_word(BIGNUM *bn, BN_ULONG value);
Adam Langley95c29f32014-06-20 12:00:00 -0700225
David Benjamin40a63112016-08-23 20:53:12 -0700226/* BN_set_u64 sets |bn| to |value|. It returns one on success or zero on
227 * allocation failure. */
228OPENSSL_EXPORT int BN_set_u64(BIGNUM *bn, uint64_t value);
229
Adam Langley95c29f32014-06-20 12:00:00 -0700230/* BN_set_negative sets the sign of |bn|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700231OPENSSL_EXPORT void BN_set_negative(BIGNUM *bn, int sign);
Adam Langley95c29f32014-06-20 12:00:00 -0700232
233/* BN_is_negative returns one if |bn| is negative and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700234OPENSSL_EXPORT int BN_is_negative(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700235
236/* BN_get_flags returns |bn->flags| & |flags|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700237OPENSSL_EXPORT int BN_get_flags(const BIGNUM *bn, int flags);
Adam Langley95c29f32014-06-20 12:00:00 -0700238
239/* BN_set_flags sets |flags| on |bn|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700240OPENSSL_EXPORT void BN_set_flags(BIGNUM *bn, int flags);
Adam Langley95c29f32014-06-20 12:00:00 -0700241
242
243/* Conversion functions. */
244
245/* BN_bin2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
246 * a big-endian number, and returns |ret|. If |ret| is NULL then a fresh
247 * |BIGNUM| is allocated and returned. It returns NULL on allocation
248 * failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700249OPENSSL_EXPORT BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret);
Adam Langley95c29f32014-06-20 12:00:00 -0700250
251/* BN_bn2bin serialises the absolute value of |in| to |out| as a big-endian
252 * integer, which must have |BN_num_bytes| of space available. It returns the
253 * number of bytes written. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700254OPENSSL_EXPORT size_t BN_bn2bin(const BIGNUM *in, uint8_t *out);
Adam Langley95c29f32014-06-20 12:00:00 -0700255
Adam Langley6887edb2014-06-20 12:00:00 -0700256/* BN_bn2bin_padded serialises the absolute value of |in| to |out| as a
257 * big-endian integer. The integer is padded with leading zeros up to size
258 * |len|. If |len| is smaller than |BN_num_bytes|, the function fails and
259 * returns 0. Otherwise, it returns 1. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700260OPENSSL_EXPORT int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in);
Adam Langley6887edb2014-06-20 12:00:00 -0700261
David Benjaminae0eaaa2015-12-17 02:01:25 -0500262/* BN_bn2cbb_padded behaves like |BN_bn2bin_padded| but writes to a |CBB|. */
263OPENSSL_EXPORT int BN_bn2cbb_padded(CBB *out, size_t len, const BIGNUM *in);
264
Adam Langley95c29f32014-06-20 12:00:00 -0700265/* BN_bn2hex returns an allocated string that contains a NUL-terminated, hex
266 * representation of |bn|. If |bn| is negative, the first char in the resulting
267 * string will be '-'. Returns NULL on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700268OPENSSL_EXPORT char *BN_bn2hex(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700269
270/* BN_hex2bn parses the leading hex number from |in|, which may be proceeded by
271 * a '-' to indicate a negative number and may contain trailing, non-hex data.
272 * If |outp| is not NULL, it constructs a BIGNUM equal to the hex number and
273 * stores it in |*outp|. If |*outp| is NULL then it allocates a new BIGNUM and
274 * updates |*outp|. It returns the number of bytes of |in| processed or zero on
275 * error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700276OPENSSL_EXPORT int BN_hex2bn(BIGNUM **outp, const char *in);
Adam Langley95c29f32014-06-20 12:00:00 -0700277
278/* BN_bn2dec returns an allocated string that contains a NUL-terminated,
279 * decimal representation of |bn|. If |bn| is negative, the first char in the
280 * resulting string will be '-'. Returns NULL on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700281OPENSSL_EXPORT char *BN_bn2dec(const BIGNUM *a);
Adam Langley95c29f32014-06-20 12:00:00 -0700282
283/* BN_dec2bn parses the leading decimal number from |in|, which may be
284 * proceeded by a '-' to indicate a negative number and may contain trailing,
285 * non-decimal data. If |outp| is not NULL, it constructs a BIGNUM equal to the
286 * decimal number and stores it in |*outp|. If |*outp| is NULL then it
287 * allocates a new BIGNUM and updates |*outp|. It returns the number of bytes
288 * of |in| processed or zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700289OPENSSL_EXPORT int BN_dec2bn(BIGNUM **outp, const char *in);
Adam Langley95c29f32014-06-20 12:00:00 -0700290
291/* BN_asc2bn acts like |BN_dec2bn| or |BN_hex2bn| depending on whether |in|
292 * begins with "0X" or "0x" (indicating hex) or not (indicating decimal). A
293 * leading '-' is still permitted and comes before the optional 0X/0x. It
294 * returns one on success or zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700295OPENSSL_EXPORT int BN_asc2bn(BIGNUM **outp, const char *in);
Adam Langley95c29f32014-06-20 12:00:00 -0700296
297/* BN_print writes a hex encoding of |a| to |bio|. It returns one on success
298 * and zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700299OPENSSL_EXPORT int BN_print(BIO *bio, const BIGNUM *a);
Adam Langley95c29f32014-06-20 12:00:00 -0700300
301/* BN_print_fp acts like |BIO_print|, but wraps |fp| in a |BIO| first. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700302OPENSSL_EXPORT int BN_print_fp(FILE *fp, const BIGNUM *a);
Adam Langley95c29f32014-06-20 12:00:00 -0700303
304/* BN_get_word returns the absolute value of |bn| as a single word. If |bn| is
305 * too large to be represented as a single word, the maximum possible value
306 * will be returned. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700307OPENSSL_EXPORT BN_ULONG BN_get_word(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700308
Rob Sloan2ee1edf2016-12-15 16:28:44 -0800309/* BN_get_u64 sets |*out| to the absolute value of |bn| as a |uint64_t| and
310 * returns one. If |bn| is too large to be represented as a |uint64_t|, it
311 * returns zero. */
312OPENSSL_EXPORT int BN_get_u64(const BIGNUM *bn, uint64_t *out);
313
Adam Langley95c29f32014-06-20 12:00:00 -0700314
David Benjaminb9c579d2015-06-11 22:52:07 -0400315/* ASN.1 functions. */
316
David Benjaminacb24512015-12-22 15:02:01 -0500317/* BN_parse_asn1_unsigned parses a non-negative DER INTEGER from |cbs| writes
318 * the result to |ret|. It returns one on success and zero on failure. */
319OPENSSL_EXPORT int BN_parse_asn1_unsigned(CBS *cbs, BIGNUM *ret);
David Benjaminb9c579d2015-06-11 22:52:07 -0400320
David Benjaminacb24512015-12-22 15:02:01 -0500321/* BN_parse_asn1_unsigned_buggy acts like |BN_parse_asn1_unsigned| but tolerates
322 * some invalid encodings. Do not use this function. */
323OPENSSL_EXPORT int BN_parse_asn1_unsigned_buggy(CBS *cbs, BIGNUM *ret);
David Benjamin231cb822015-09-15 16:47:35 -0400324
David Benjaminacb24512015-12-22 15:02:01 -0500325/* BN_marshal_asn1 marshals |bn| as a non-negative DER INTEGER and appends the
326 * result to |cbb|. It returns one on success and zero on failure. */
327OPENSSL_EXPORT int BN_marshal_asn1(CBB *cbb, const BIGNUM *bn);
David Benjaminb9c579d2015-06-11 22:52:07 -0400328
329
Adam Langleyb8b54782014-08-13 10:31:52 -0700330/* Internal functions.
331 *
332 * These functions are useful for code that is doing low-level manipulations of
333 * BIGNUM values. However, be sure that no other function in this file does
334 * what you want before turning to these. */
335
336/* bn_correct_top decrements |bn->top| until |bn->d[top-1]| is non-zero or
David Benjamin899b9b12016-08-02 13:09:19 -0400337 * until |top| is zero. If |bn| is zero, |bn->neg| is set to zero. */
Adam Langleyb8b54782014-08-13 10:31:52 -0700338OPENSSL_EXPORT void bn_correct_top(BIGNUM *bn);
339
340/* bn_wexpand ensures that |bn| has at least |words| works of space without
David Benjamin4c4ff022016-08-23 10:09:04 -0700341 * altering its value. It returns |bn| on success or NULL on allocation
Adam Langleyb8b54782014-08-13 10:31:52 -0700342 * failure. */
David Benjamin719220e2015-08-11 12:05:02 -0400343OPENSSL_EXPORT BIGNUM *bn_wexpand(BIGNUM *bn, size_t words);
Adam Langleyb8b54782014-08-13 10:31:52 -0700344
345
Adam Langley95c29f32014-06-20 12:00:00 -0700346/* BIGNUM pools.
347 *
348 * Certain BIGNUM operations need to use many temporary variables and
349 * allocating and freeing them can be quite slow. Thus such opertions typically
350 * take a |BN_CTX| parameter, which contains a pool of |BIGNUMs|. The |ctx|
351 * argument to a public function may be NULL, in which case a local |BN_CTX|
352 * will be created just for the lifetime of that call.
353 *
354 * A function must call |BN_CTX_start| first. Then, |BN_CTX_get| may be called
355 * repeatedly to obtain temporary |BIGNUM|s. All |BN_CTX_get| calls must be made
356 * before calling any other functions that use the |ctx| as an argument.
357 *
358 * Finally, |BN_CTX_end| must be called before returning from the function.
359 * When |BN_CTX_end| is called, the |BIGNUM| pointers obtained from
360 * |BN_CTX_get| become invalid. */
361
362/* BN_CTX_new returns a new, empty BN_CTX or NULL on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700363OPENSSL_EXPORT BN_CTX *BN_CTX_new(void);
Adam Langley95c29f32014-06-20 12:00:00 -0700364
365/* BN_CTX_free frees all BIGNUMs contained in |ctx| and then frees |ctx|
366 * itself. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700367OPENSSL_EXPORT void BN_CTX_free(BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700368
369/* BN_CTX_start "pushes" a new entry onto the |ctx| stack and allows future
370 * calls to |BN_CTX_get|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700371OPENSSL_EXPORT void BN_CTX_start(BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700372
373/* BN_CTX_get returns a new |BIGNUM|, or NULL on allocation failure. Once
374 * |BN_CTX_get| has returned NULL, all future calls will also return NULL until
375 * |BN_CTX_end| is called. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700376OPENSSL_EXPORT BIGNUM *BN_CTX_get(BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700377
378/* BN_CTX_end invalidates all |BIGNUM|s returned from |BN_CTX_get| since the
379 * matching |BN_CTX_start| call. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700380OPENSSL_EXPORT void BN_CTX_end(BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700381
382
383/* Simple arithmetic */
384
385/* BN_add sets |r| = |a| + |b|, where |r| may be the same pointer as either |a|
386 * or |b|. It returns one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700387OPENSSL_EXPORT int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
Adam Langley95c29f32014-06-20 12:00:00 -0700388
389/* BN_uadd sets |r| = |a| + |b|, where |a| and |b| are non-negative and |r| may
390 * be the same pointer as either |a| or |b|. It returns one on success and zero
391 * on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700392OPENSSL_EXPORT int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
Adam Langley95c29f32014-06-20 12:00:00 -0700393
394/* BN_add_word adds |w| to |a|. It returns one on success and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700395OPENSSL_EXPORT int BN_add_word(BIGNUM *a, BN_ULONG w);
Adam Langley95c29f32014-06-20 12:00:00 -0700396
Brian Smithe4bf8b32016-07-01 13:36:06 -1000397/* BN_sub sets |r| = |a| - |b|, where |r| may be the same pointer as either |a|
398 * or |b|. It returns one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700399OPENSSL_EXPORT int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
Adam Langley95c29f32014-06-20 12:00:00 -0700400
David Benjamin25c93ff2014-08-27 12:09:26 -0400401/* BN_usub sets |r| = |a| - |b|, where |a| and |b| are non-negative integers,
Brian Smith3d4030b2016-07-01 14:12:40 -1000402 * |b| < |a| and |r| may be the same pointer as either |a| or |b|. It returns
Adam Langley95c29f32014-06-20 12:00:00 -0700403 * one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700404OPENSSL_EXPORT int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
Adam Langley95c29f32014-06-20 12:00:00 -0700405
406/* BN_sub_word subtracts |w| from |a|. It returns one on success and zero on
407 * allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700408OPENSSL_EXPORT int BN_sub_word(BIGNUM *a, BN_ULONG w);
Adam Langley95c29f32014-06-20 12:00:00 -0700409
410/* BN_mul sets |r| = |a| * |b|, where |r| may be the same pointer as |a| or
411 * |b|. Returns one on success and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700412OPENSSL_EXPORT int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
413 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700414
415/* BN_mul_word sets |bn| = |bn| * |w|. It returns one on success or zero on
416 * allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700417OPENSSL_EXPORT int BN_mul_word(BIGNUM *bn, BN_ULONG w);
Adam Langley95c29f32014-06-20 12:00:00 -0700418
419/* BN_sqr sets |r| = |a|^2 (i.e. squares), where |r| may be the same pointer as
420 * |a|. Returns one on success and zero otherwise. This is more efficient than
421 * BN_mul(r, a, a, ctx). */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700422OPENSSL_EXPORT int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700423
424/* BN_div divides |numerator| by |divisor| and places the result in |quotient|
425 * and the remainder in |rem|. Either of |quotient| or |rem| may be NULL, in
426 * which case the respective value is not returned. The result is rounded
427 * towards zero; thus if |numerator| is negative, the remainder will be zero or
428 * negative. It returns one on success or zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700429OPENSSL_EXPORT int BN_div(BIGNUM *quotient, BIGNUM *rem,
430 const BIGNUM *numerator, const BIGNUM *divisor,
431 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700432
433/* BN_div_word sets |numerator| = |numerator|/|divisor| and returns the
434 * remainder or (BN_ULONG)-1 on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700435OPENSSL_EXPORT BN_ULONG BN_div_word(BIGNUM *numerator, BN_ULONG divisor);
Adam Langley95c29f32014-06-20 12:00:00 -0700436
Adam Langley409766d2014-06-20 12:00:00 -0700437/* BN_sqrt sets |*out_sqrt| (which may be the same |BIGNUM| as |in|) to the
438 * square root of |in|, using |ctx|. It returns one on success or zero on
439 * error. Negative numbers and non-square numbers will result in an error with
440 * appropriate errors on the error queue. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700441OPENSSL_EXPORT int BN_sqrt(BIGNUM *out_sqrt, const BIGNUM *in, BN_CTX *ctx);
Adam Langley409766d2014-06-20 12:00:00 -0700442
Adam Langley95c29f32014-06-20 12:00:00 -0700443
444/* Comparison functions */
445
446/* BN_cmp returns a value less than, equal to or greater than zero if |a| is
447 * less than, equal to or greater than |b|, respectively. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700448OPENSSL_EXPORT int BN_cmp(const BIGNUM *a, const BIGNUM *b);
Adam Langley95c29f32014-06-20 12:00:00 -0700449
Brian Smith4edca0b2016-07-25 10:36:58 -1000450/* BN_cmp_word is like |BN_cmp| except it takes its second argument as a
451 * |BN_ULONG| instead of a |BIGNUM|. */
David Benjaminccd511e2016-07-29 12:11:34 -0400452OPENSSL_EXPORT int BN_cmp_word(const BIGNUM *a, BN_ULONG b);
Brian Smith4edca0b2016-07-25 10:36:58 -1000453
Adam Langley95c29f32014-06-20 12:00:00 -0700454/* BN_ucmp returns a value less than, equal to or greater than zero if the
455 * absolute value of |a| is less than, equal to or greater than the absolute
456 * value of |b|, respectively. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700457OPENSSL_EXPORT int BN_ucmp(const BIGNUM *a, const BIGNUM *b);
Adam Langley95c29f32014-06-20 12:00:00 -0700458
Brian Smith86080c32016-03-25 12:23:16 -1000459/* BN_equal_consttime returns one if |a| is equal to |b|, and zero otherwise.
460 * It takes an amount of time dependent on the sizes of |a| and |b|, but
461 * independent of the contents (including the signs) of |a| and |b|. */
462OPENSSL_EXPORT int BN_equal_consttime(const BIGNUM *a, const BIGNUM *b);
463
Adam Langley95c29f32014-06-20 12:00:00 -0700464/* BN_abs_is_word returns one if the absolute value of |bn| equals |w| and zero
465 * otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700466OPENSSL_EXPORT int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w);
Adam Langley95c29f32014-06-20 12:00:00 -0700467
468/* BN_is_zero returns one if |bn| is zero and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700469OPENSSL_EXPORT int BN_is_zero(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700470
471/* BN_is_one returns one if |bn| equals one and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700472OPENSSL_EXPORT int BN_is_one(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700473
474/* BN_is_word returns one if |bn| is exactly |w| and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700475OPENSSL_EXPORT int BN_is_word(const BIGNUM *bn, BN_ULONG w);
Adam Langley95c29f32014-06-20 12:00:00 -0700476
477/* BN_is_odd returns one if |bn| is odd and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700478OPENSSL_EXPORT int BN_is_odd(const BIGNUM *bn);
Adam Langley95c29f32014-06-20 12:00:00 -0700479
480
481/* Bitwise operations. */
482
483/* BN_lshift sets |r| equal to |a| << n. The |a| and |r| arguments may be the
484 * same |BIGNUM|. It returns one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700485OPENSSL_EXPORT int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700486
487/* BN_lshift1 sets |r| equal to |a| << 1, where |r| and |a| may be the same
488 * pointer. It returns one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700489OPENSSL_EXPORT int BN_lshift1(BIGNUM *r, const BIGNUM *a);
Adam Langley95c29f32014-06-20 12:00:00 -0700490
491/* BN_rshift sets |r| equal to |a| >> n, where |r| and |a| may be the same
492 * pointer. It returns one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700493OPENSSL_EXPORT int BN_rshift(BIGNUM *r, const BIGNUM *a, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700494
495/* BN_rshift1 sets |r| equal to |a| >> 1, where |r| and |a| may be the same
496 * pointer. It returns one on success and zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700497OPENSSL_EXPORT int BN_rshift1(BIGNUM *r, const BIGNUM *a);
Adam Langley95c29f32014-06-20 12:00:00 -0700498
499/* BN_set_bit sets the |n|th, least-significant bit in |a|. For example, if |a|
500 * is 2 then setting bit zero will make it 3. It returns one on success or zero
501 * on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700502OPENSSL_EXPORT int BN_set_bit(BIGNUM *a, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700503
504/* BN_clear_bit clears the |n|th, least-significant bit in |a|. For example, if
505 * |a| is 3, clearing bit zero will make it two. It returns one on success or
506 * zero on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700507OPENSSL_EXPORT int BN_clear_bit(BIGNUM *a, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700508
509/* BN_is_bit_set returns the value of the |n|th, least-significant bit in |a|,
510 * or zero if the bit doesn't exist. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700511OPENSSL_EXPORT int BN_is_bit_set(const BIGNUM *a, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700512
513/* BN_mask_bits truncates |a| so that it is only |n| bits long. It returns one
514 * on success or zero if |n| is greater than the length of |a| already. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700515OPENSSL_EXPORT int BN_mask_bits(BIGNUM *a, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700516
517
518/* Modulo arithmetic. */
519
David Benjamin44bedc32016-06-23 16:05:02 -0400520/* BN_mod_word returns |a| mod |w| or (BN_ULONG)-1 on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700521OPENSSL_EXPORT BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
Adam Langley95c29f32014-06-20 12:00:00 -0700522
523/* BN_mod is a helper macro that calls |BN_div| and discards the quotient. */
524#define BN_mod(rem, numerator, divisor, ctx) \
525 BN_div(NULL, (rem), (numerator), (divisor), (ctx))
526
527/* BN_nnmod is a non-negative modulo function. It acts like |BN_mod|, but 0 <=
David Benjamina5974bf2015-03-25 23:49:37 -0400528 * |rem| < |divisor| is always true. It returns one on success and zero on
529 * error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700530OPENSSL_EXPORT int BN_nnmod(BIGNUM *rem, const BIGNUM *numerator,
531 const BIGNUM *divisor, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700532
533/* BN_mod_add sets |r| = |a| + |b| mod |m|. It returns one on success and zero
534 * on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700535OPENSSL_EXPORT int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
536 const BIGNUM *m, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700537
538/* BN_mod_add_quick acts like |BN_mod_add| but requires that |a| and |b| be
539 * non-negative and less than |m|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700540OPENSSL_EXPORT int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
541 const BIGNUM *m);
Adam Langley95c29f32014-06-20 12:00:00 -0700542
543/* BN_mod_sub sets |r| = |a| - |b| mod |m|. It returns one on success and zero
544 * on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700545OPENSSL_EXPORT int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
546 const BIGNUM *m, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700547
548/* BN_mod_sub_quick acts like |BN_mod_sub| but requires that |a| and |b| be
549 * non-negative and less than |m|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700550OPENSSL_EXPORT int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
551 const BIGNUM *m);
Adam Langley95c29f32014-06-20 12:00:00 -0700552
553/* BN_mod_mul sets |r| = |a|*|b| mod |m|. It returns one on success and zero
554 * on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700555OPENSSL_EXPORT int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
556 const BIGNUM *m, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700557
Adam Langley5f889992015-11-04 14:05:00 -0800558/* BN_mod_sqr sets |r| = |a|^2 mod |m|. It returns one on success and zero
Adam Langley95c29f32014-06-20 12:00:00 -0700559 * on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700560OPENSSL_EXPORT int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
561 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700562
563/* BN_mod_lshift sets |r| = (|a| << n) mod |m|, where |r| and |a| may be the
564 * same pointer. It returns one on success and zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700565OPENSSL_EXPORT int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n,
566 const BIGNUM *m, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700567
568/* BN_mod_lshift_quick acts like |BN_mod_lshift| but requires that |a| be
569 * non-negative and less than |m|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700570OPENSSL_EXPORT int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n,
571 const BIGNUM *m);
Adam Langley95c29f32014-06-20 12:00:00 -0700572
573/* BN_mod_lshift1 sets |r| = (|a| << 1) mod |m|, where |r| and |a| may be the
574 * same pointer. It returns one on success and zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700575OPENSSL_EXPORT int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
576 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700577
578/* BN_mod_lshift1_quick acts like |BN_mod_lshift1| but requires that |a| be
579 * non-negative and less than |m|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700580OPENSSL_EXPORT int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a,
581 const BIGNUM *m);
Adam Langley95c29f32014-06-20 12:00:00 -0700582
David Benjaminbd691752016-11-25 15:10:17 -0500583/* BN_mod_sqrt returns a newly-allocated |BIGNUM|, r, such that
584 * r^2 == a (mod p). |p| must be a prime. It returns NULL on error or if |a| is
585 * not a square mod |p|. In the latter case, it will add |BN_R_NOT_A_SQUARE| to
586 * the error queue. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700587OPENSSL_EXPORT BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p,
588 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700589
590
591/* Random and prime number generation. */
592
David Benjamind224d522016-08-16 10:03:45 -0400593/* The following are values for the |top| parameter of |BN_rand|. */
David Benjamin1e5ac5d2016-11-01 16:37:09 -0400594#define BN_RAND_TOP_ANY (-1)
David Benjamind224d522016-08-16 10:03:45 -0400595#define BN_RAND_TOP_ONE 0
596#define BN_RAND_TOP_TWO 1
597
598/* The following are values for the |bottom| parameter of |BN_rand|. */
599#define BN_RAND_BOTTOM_ANY 0
600#define BN_RAND_BOTTOM_ODD 1
601
602/* BN_rand sets |rnd| to a random number of length |bits|. It returns one on
603 * success and zero otherwise.
Adam Langley95c29f32014-06-20 12:00:00 -0700604 *
David Benjamind224d522016-08-16 10:03:45 -0400605 * |top| must be one of the |BN_RAND_TOP_*| values. If |BN_RAND_TOP_ONE|, the
606 * most-significant bit, if any, will be set. If |BN_RAND_TOP_TWO|, the two
607 * most significant bits, if any, will be set. If |BN_RAND_TOP_ANY|, no extra
608 * action will be taken and |BN_num_bits(rnd)| may not equal |bits| if the most
609 * significant bits randomly ended up as zeros.
Adam Langley95c29f32014-06-20 12:00:00 -0700610 *
David Benjamind224d522016-08-16 10:03:45 -0400611 * |bottom| must be one of the |BN_RAND_BOTTOM_*| values. If
612 * |BN_RAND_BOTTOM_ODD|, the least-significant bit, if any, will be set. If
613 * |BN_RAND_BOTTOM_ANY|, no extra action will be taken. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700614OPENSSL_EXPORT int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
Adam Langley95c29f32014-06-20 12:00:00 -0700615
616/* BN_pseudo_rand is an alias for |BN_rand|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700617OPENSSL_EXPORT int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
Adam Langley95c29f32014-06-20 12:00:00 -0700618
Brian Smith4edca0b2016-07-25 10:36:58 -1000619/* BN_rand_range is equivalent to |BN_rand_range_ex| with |min_inclusive| set
620 * to zero and |max_exclusive| set to |range|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700621OPENSSL_EXPORT int BN_rand_range(BIGNUM *rnd, const BIGNUM *range);
Adam Langley95c29f32014-06-20 12:00:00 -0700622
Brian Smith4edca0b2016-07-25 10:36:58 -1000623/* BN_rand_range_ex sets |rnd| to a random value in
624 * [min_inclusive..max_exclusive). It returns one on success and zero
625 * otherwise. */
626OPENSSL_EXPORT int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive,
627 const BIGNUM *max_exclusive);
628
Adam Langley95c29f32014-06-20 12:00:00 -0700629/* BN_pseudo_rand_range is an alias for BN_rand_range. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700630OPENSSL_EXPORT int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range);
Adam Langley95c29f32014-06-20 12:00:00 -0700631
Adam Langleyd4b4f082014-06-20 12:00:00 -0700632/* BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike
633 * BN_rand_range, it also includes the contents of |priv| and |message| in the
634 * generation so that an RNG failure isn't fatal as long as |priv| remains
635 * secret. This is intended for use in DSA and ECDSA where an RNG weakness
636 * leads directly to private key exposure unless this function is used.
637 * It returns one on success and zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700638OPENSSL_EXPORT int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range,
639 const BIGNUM *priv,
640 const uint8_t *message,
641 size_t message_len, BN_CTX *ctx);
Adam Langleyd4b4f082014-06-20 12:00:00 -0700642
Adam Langley95c29f32014-06-20 12:00:00 -0700643/* BN_GENCB holds a callback function that is used by generation functions that
644 * can take a very long time to complete. Use |BN_GENCB_set| to initialise a
645 * |BN_GENCB| structure.
646 *
647 * The callback receives the address of that |BN_GENCB| structure as its last
648 * argument and the user is free to put an arbitary pointer in |arg|. The other
649 * arguments are set as follows:
650 * event=BN_GENCB_GENERATED, n=i: after generating the i'th possible prime
651 * number.
652 * event=BN_GENCB_PRIME_TEST, n=-1: when finished trial division primality
653 * checks.
654 * event=BN_GENCB_PRIME_TEST, n=i: when the i'th primality test has finished.
655 *
656 * The callback can return zero to abort the generation progress or one to
657 * allow it to continue.
658 *
659 * When other code needs to call a BN generation function it will often take a
660 * BN_GENCB argument and may call the function with other argument values. */
661#define BN_GENCB_GENERATED 0
662#define BN_GENCB_PRIME_TEST 1
663
664struct bn_gencb_st {
665 void *arg; /* callback-specific data */
666 int (*callback)(int event, int n, struct bn_gencb_st *);
667};
668
669/* BN_GENCB_set configures |callback| to call |f| and sets |callout->arg| to
670 * |arg|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700671OPENSSL_EXPORT void BN_GENCB_set(BN_GENCB *callback,
672 int (*f)(int event, int n,
673 struct bn_gencb_st *),
674 void *arg);
Adam Langley95c29f32014-06-20 12:00:00 -0700675
676/* BN_GENCB_call calls |callback|, if not NULL, and returns the return value of
677 * the callback, or 1 if |callback| is NULL. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700678OPENSSL_EXPORT int BN_GENCB_call(BN_GENCB *callback, int event, int n);
Adam Langley95c29f32014-06-20 12:00:00 -0700679
680/* BN_generate_prime_ex sets |ret| to a prime number of |bits| length. If safe
681 * is non-zero then the prime will be such that (ret-1)/2 is also a prime.
682 * (This is needed for Diffie-Hellman groups to ensure that the only subgroups
683 * are of size 2 and (p-1)/2.).
684 *
685 * If |add| is not NULL, the prime will fulfill the condition |ret| % |add| ==
686 * |rem| in order to suit a given generator. (If |rem| is NULL then |ret| %
687 * |add| == 1.)
688 *
689 * If |cb| is not NULL, it will be called during processing to give an
690 * indication of progress. See the comments for |BN_GENCB|. It returns one on
691 * success and zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700692OPENSSL_EXPORT int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
693 const BIGNUM *add, const BIGNUM *rem,
694 BN_GENCB *cb);
Adam Langley95c29f32014-06-20 12:00:00 -0700695
696/* BN_prime_checks is magic value that can be used as the |checks| argument to
697 * the primality testing functions in order to automatically select a number of
698 * Miller-Rabin checks that gives a false positive rate of ~2^{-80}. */
699#define BN_prime_checks 0
700
701/* BN_primality_test sets |*is_probably_prime| to one if |candidate| is
702 * probably a prime number by the Miller-Rabin test or zero if it's certainly
703 * not.
704 *
705 * If |do_trial_division| is non-zero then |candidate| will be tested against a
706 * list of small primes before Miller-Rabin tests. The probability of this
707 * function returning a false positive is 2^{2*checks}. If |checks| is
708 * |BN_prime_checks| then a value that results in approximately 2^{-80} false
709 * positive probability is used. If |cb| is not NULL then it is called during
710 * the checking process. See the comment above |BN_GENCB|.
711 *
712 * The function returns one on success and zero on error.
713 *
714 * (If you are unsure whether you want |do_trial_division|, don't set it.) */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700715OPENSSL_EXPORT int BN_primality_test(int *is_probably_prime,
716 const BIGNUM *candidate, int checks,
717 BN_CTX *ctx, int do_trial_division,
718 BN_GENCB *cb);
Adam Langley95c29f32014-06-20 12:00:00 -0700719
720/* BN_is_prime_fasttest_ex returns one if |candidate| is probably a prime
721 * number by the Miller-Rabin test, zero if it's certainly not and -1 on error.
722 *
723 * If |do_trial_division| is non-zero then |candidate| will be tested against a
724 * list of small primes before Miller-Rabin tests. The probability of this
725 * function returning one when |candidate| is composite is 2^{2*checks}. If
726 * |checks| is |BN_prime_checks| then a value that results in approximately
727 * 2^{-80} false positive probability is used. If |cb| is not NULL then it is
728 * called during the checking process. See the comment above |BN_GENCB|.
729 *
730 * WARNING: deprecated. Use |BN_primality_test|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700731OPENSSL_EXPORT int BN_is_prime_fasttest_ex(const BIGNUM *candidate, int checks,
732 BN_CTX *ctx, int do_trial_division,
733 BN_GENCB *cb);
Adam Langley95c29f32014-06-20 12:00:00 -0700734
735/* BN_is_prime_ex acts the same as |BN_is_prime_fasttest_ex| with
736 * |do_trial_division| set to zero.
737 *
738 * WARNING: deprecated: Use |BN_primality_test|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700739OPENSSL_EXPORT int BN_is_prime_ex(const BIGNUM *candidate, int checks,
740 BN_CTX *ctx, BN_GENCB *cb);
Adam Langley95c29f32014-06-20 12:00:00 -0700741
742
743/* Number theory functions */
744
745/* BN_gcd sets |r| = gcd(|a|, |b|). It returns one on success and zero
746 * otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700747OPENSSL_EXPORT int BN_gcd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
748 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700749
Brian Smithec3cb3a2016-07-25 15:35:20 -1000750/* BN_mod_inverse sets |out| equal to |a|^-1, mod |n|. If |out| is NULL, a
751 * fresh BIGNUM is allocated. It returns the result or NULL on error.
752 *
753 * If either of |a| or |n| have |BN_FLG_CONSTTIME| set then the operation is
754 * performed using an algorithm that avoids some branches but which isn't
755 * constant-time. This function shouldn't be used for secret values, even
756 * with |BN_FLG_CONSTTIME|; use |BN_mod_inverse_blinded| instead. Or, if
757 * |n| is guaranteed to be prime, use
758 * |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
759 * advantage of Fermat's Little Theorem. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700760OPENSSL_EXPORT BIGNUM *BN_mod_inverse(BIGNUM *out, const BIGNUM *a,
761 const BIGNUM *n, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700762
Brian Smithec3cb3a2016-07-25 15:35:20 -1000763/* BN_mod_inverse_blinded sets |out| equal to |a|^-1, mod |n|, where |n| is the
764 * Montgomery modulus for |mont|. |a| must be non-negative and must be less
765 * than |n|. |n| must be greater than 1. |a| is blinded (masked by a random
766 * value) to protect it against side-channel attacks. |BN_mod_inverse_blinded|
767 * may or may not ignore the |BN_FLG_CONSTTIME| flag on any/all of its inputs.
768 * It returns one on success or zero on failure. On failure, if the failure was
769 * caused by |a| having no inverse mod |n| then |*out_no_inverse| will be set
770 * to one; otherwise it will be set to zero. */
771int BN_mod_inverse_blinded(BIGNUM *out, int *out_no_inverse, const BIGNUM *a,
772 const BN_MONT_CTX *mont, BN_CTX *ctx);
Adam Langley06fa67c2015-09-08 16:31:33 -0700773
Brian Smitha4327572016-08-02 16:58:57 -1000774/* BN_mod_inverse_odd sets |out| equal to |a|^-1, mod |n|. |a| must be
775 * non-negative and must be less than |n|. |n| must be odd. This function
776 * shouldn't be used for secret values; use |BN_mod_inverse_blinded| instead.
777 * Or, if |n| is guaranteed to be prime, use
778 * |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
779 * advantage of Fermat's Little Theorem. It returns one on success or zero on
780 * failure. On failure, if the failure was caused by |a| having no inverse mod
781 * |n| then |*out_no_inverse| will be set to one; otherwise it will be set to
782 * zero. */
783int BN_mod_inverse_odd(BIGNUM *out, int *out_no_inverse, const BIGNUM *a,
784 const BIGNUM *n, BN_CTX *ctx);
785
Adam Langley95c29f32014-06-20 12:00:00 -0700786/* BN_kronecker returns the Kronecker symbol of |a| and |b| (which is -1, 0 or
787 * 1), or -2 on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700788OPENSSL_EXPORT int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700789
790
791/* Montgomery arithmetic. */
792
793/* BN_MONT_CTX contains the precomputed values needed to work in a specific
794 * Montgomery domain. */
795
796/* BN_MONT_CTX_new returns a fresh BN_MONT_CTX or NULL on allocation failure. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700797OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new(void);
Adam Langley95c29f32014-06-20 12:00:00 -0700798
David Benjamin12f77372015-10-26 11:31:51 -0400799/* BN_MONT_CTX_free frees memory associated with |mont|. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700800OPENSSL_EXPORT void BN_MONT_CTX_free(BN_MONT_CTX *mont);
Adam Langley95c29f32014-06-20 12:00:00 -0700801
802/* BN_MONT_CTX_copy sets |to| equal to |from|. It returns |to| on success or
803 * NULL on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700804OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to,
David Benjamine82e6f62015-11-03 10:40:23 -0500805 const BN_MONT_CTX *from);
Adam Langley95c29f32014-06-20 12:00:00 -0700806
807/* BN_MONT_CTX_set sets up a Montgomery context given the modulus, |mod|. It
808 * returns one on success and zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700809OPENSSL_EXPORT int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod,
810 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700811
Adam Langley683d7bd2015-04-13 11:04:14 -0700812/* BN_MONT_CTX_set_locked takes |lock| and checks whether |*pmont| is NULL. If
813 * so, it creates a new |BN_MONT_CTX| and sets the modulus for it to |mod|. It
Brian Smithd0357302016-03-25 10:11:04 -1000814 * then stores it as |*pmont|. It returns one on success and zero on error.
Adam Langley95c29f32014-06-20 12:00:00 -0700815 *
Brian Smithd0357302016-03-25 10:11:04 -1000816 * If |*pmont| is already non-NULL then it does nothing and returns one. */
817int BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_MUTEX *lock,
818 const BIGNUM *mod, BN_CTX *bn_ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700819
Brian Smith78f84f42016-07-30 21:17:10 -1000820/* BN_to_montgomery sets |ret| equal to |a| in the Montgomery domain. |a| is
821 * assumed to be in the range [0, n), where |n| is the Montgomery modulus. It
822 * returns one on success or zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700823OPENSSL_EXPORT int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a,
824 const BN_MONT_CTX *mont, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700825
Brian Smith78f84f42016-07-30 21:17:10 -1000826/* BN_from_montgomery sets |ret| equal to |a| * R^-1, i.e. translates values out
827 * of the Montgomery domain. |a| is assumed to be in the range [0, n), where |n|
828 * is the Montgomery modulus. It returns one on success or zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700829OPENSSL_EXPORT int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a,
830 const BN_MONT_CTX *mont, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700831
832/* BN_mod_mul_montgomery set |r| equal to |a| * |b|, in the Montgomery domain.
833 * Both |a| and |b| must already be in the Montgomery domain (by
Brian Smith78f84f42016-07-30 21:17:10 -1000834 * |BN_to_montgomery|). In particular, |a| and |b| are assumed to be in the
835 * range [0, n), where |n| is the Montgomery modulus. It returns one on success
836 * or zero on error. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700837OPENSSL_EXPORT int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a,
838 const BIGNUM *b,
839 const BN_MONT_CTX *mont, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700840
841
842/* Exponentiation. */
843
844/* BN_exp sets |r| equal to |a|^{|p|}. It does so with a square-and-multiply
845 * algorithm that leaks side-channel information. It returns one on success or
846 * zero otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700847OPENSSL_EXPORT int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
848 BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700849
Adam Langley5d17dd62014-06-30 14:22:32 -0700850/* BN_mod_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
Adam Langley95c29f32014-06-20 12:00:00 -0700851 * algorithm for the values provided and can run in constant time if
852 * |BN_FLG_CONSTTIME| is set for |p|. It returns one on success or zero
853 * otherwise. */
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700854OPENSSL_EXPORT int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
855 const BIGNUM *m, BN_CTX *ctx);
Adam Langley95c29f32014-06-20 12:00:00 -0700856
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700857OPENSSL_EXPORT int BN_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
858 const BIGNUM *m, BN_CTX *ctx,
David Benjamine82e6f62015-11-03 10:40:23 -0500859 const BN_MONT_CTX *mont);
Adam Langley95c29f32014-06-20 12:00:00 -0700860
Adam Langleyeb7d2ed2014-07-30 16:02:14 -0700861OPENSSL_EXPORT int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a,
862 const BIGNUM *p, const BIGNUM *m,
Adam Langleyefb42fb2015-11-02 17:39:02 -0800863 BN_CTX *ctx,
864 const BN_MONT_CTX *mont);
Adam Langley95c29f32014-06-20 12:00:00 -0700865
Adam Langley95c29f32014-06-20 12:00:00 -0700866
Matt Braithwaite64887252015-08-11 17:17:28 -0700867/* Deprecated functions */
868
869/* BN_bn2mpi serialises the value of |in| to |out|, using a format that consists
870 * of the number's length in bytes represented as a 4-byte big-endian number,
871 * and the number itself in big-endian format, where the most significant bit
872 * signals a negative number. (The representation of numbers with the MSB set is
873 * prefixed with null byte). |out| must have sufficient space available; to
874 * find the needed amount of space, call the function with |out| set to NULL. */
875OPENSSL_EXPORT size_t BN_bn2mpi(const BIGNUM *in, uint8_t *out);
876
Adam Langley5f889992015-11-04 14:05:00 -0800877/* BN_mpi2bn parses |len| bytes from |in| and returns the resulting value. The
Matt Braithwaite64887252015-08-11 17:17:28 -0700878 * bytes at |in| are expected to be in the format emitted by |BN_bn2mpi|.
879 *
880 * If |out| is NULL then a fresh |BIGNUM| is allocated and returned, otherwise
881 * |out| is reused and returned. On error, NULL is returned and the error queue
882 * is updated. */
883OPENSSL_EXPORT BIGNUM *BN_mpi2bn(const uint8_t *in, size_t len, BIGNUM *out);
884
Brian Smithe31d1032016-04-21 17:08:13 -1000885/* BN_mod_exp_mont_word is like |BN_mod_exp_mont| except that the base |a| is
886 * given as a |BN_ULONG| instead of a |BIGNUM *|. It returns one on success
887 * or zero otherwise. */
888OPENSSL_EXPORT int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
889 const BIGNUM *m, BN_CTX *ctx,
890 const BN_MONT_CTX *mont);
891
Brian Smith448fa422016-04-21 17:08:29 -1000892/* BN_mod_exp2_mont calculates (a1^p1) * (a2^p2) mod m. It returns 1 on success
893 * or zero otherwise. */
894OPENSSL_EXPORT int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1,
895 const BIGNUM *p1, const BIGNUM *a2,
896 const BIGNUM *p2, const BIGNUM *m,
897 BN_CTX *ctx, const BN_MONT_CTX *mont);
898
Matt Braithwaite64887252015-08-11 17:17:28 -0700899
Adam Langley95c29f32014-06-20 12:00:00 -0700900/* Private functions */
901
902struct bignum_st {
903 BN_ULONG *d; /* Pointer to an array of 'BN_BITS2' bit chunks in little-endian
904 order. */
905 int top; /* Index of last used element in |d|, plus one. */
906 int dmax; /* Size of |d|, in words. */
907 int neg; /* one if the number is negative */
908 int flags; /* bitmask of BN_FLG_* values */
909};
910
911struct bn_mont_ctx_st {
912 BIGNUM RR; /* used to convert to montgomery form */
913 BIGNUM N; /* The modulus */
Brian Smith8bde5d22015-11-11 18:36:23 -1000914 BN_ULONG n0[2]; /* least significant words of (R*Ri-1)/N */
Adam Langley95c29f32014-06-20 12:00:00 -0700915};
916
Adam Langley214cd442014-08-18 11:35:45 -0700917OPENSSL_EXPORT unsigned BN_num_bits_word(BN_ULONG l);
Adam Langley95c29f32014-06-20 12:00:00 -0700918
919#define BN_FLG_MALLOCED 0x01
920#define BN_FLG_STATIC_DATA 0x02
Brian Smith9f05de42016-08-02 18:21:18 -1000921/* Avoid leaking exponent information through timing. |BN_mod_exp_mont| will
922 * call |BN_mod_exp_mont_consttime| and |BN_mod_inverse| will call
923 * |BN_mod_inverse_no_branch|. */
Adam Langley95c29f32014-06-20 12:00:00 -0700924#define BN_FLG_CONSTTIME 0x04
925
926
927#if defined(__cplusplus)
928} /* extern C */
Matt Braithwaited17d74d2016-08-17 20:10:28 -0700929
930extern "C++" {
931
932namespace bssl {
933
Matt Braithwaited17d74d2016-08-17 20:10:28 -0700934BORINGSSL_MAKE_DELETER(BIGNUM, BN_free)
935BORINGSSL_MAKE_DELETER(BN_CTX, BN_CTX_free)
936BORINGSSL_MAKE_DELETER(BN_MONT_CTX, BN_MONT_CTX_free)
937
Matt Braithwaited17d74d2016-08-17 20:10:28 -0700938} // namespace bssl
939
940} /* extern C++ */
941
Adam Langley95c29f32014-06-20 12:00:00 -0700942#endif
943
David Benjamin689be0f2015-02-11 15:55:26 -0500944#define BN_R_ARG2_LT_ARG3 100
945#define BN_R_BAD_RECIPROCAL 101
946#define BN_R_BIGNUM_TOO_LONG 102
947#define BN_R_BITS_TOO_SMALL 103
948#define BN_R_CALLED_WITH_EVEN_MODULUS 104
949#define BN_R_DIV_BY_ZERO 105
950#define BN_R_EXPAND_ON_STATIC_BIGNUM_DATA 106
951#define BN_R_INPUT_NOT_REDUCED 107
952#define BN_R_INVALID_RANGE 108
953#define BN_R_NEGATIVE_NUMBER 109
954#define BN_R_NOT_A_SQUARE 110
955#define BN_R_NOT_INITIALIZED 111
956#define BN_R_NO_INVERSE 112
957#define BN_R_PRIVATE_KEY_TOO_LARGE 113
958#define BN_R_P_IS_NOT_PRIME 114
959#define BN_R_TOO_MANY_ITERATIONS 115
960#define BN_R_TOO_MANY_TEMPORARY_VARIABLES 116
David Benjaminb9c579d2015-06-11 22:52:07 -0400961#define BN_R_BAD_ENCODING 117
962#define BN_R_ENCODE_ERROR 118
Adam Langley95c29f32014-06-20 12:00:00 -0700963
964#endif /* OPENSSL_HEADER_BN_H */