1/* 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>
127#include <openssl/thread.h>
128
129#include <inttypes.h> // for PRIu64 and friends
130#include <stdio.h> // for FILE*
131
132#if defined(__cplusplus)
133extern "C" {
134#endif
135
136
137// BN provides support for working with arbitrary 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
142// 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. This is due to text in C99 which
146// was never adopted in any C++ standard and explicitly overruled in C++11. As
147// this is a public header, bn.h does not define |__STDC_FORMAT_MACROS| itself.
148// Projects which use |BN_*_FMT*| with outdated C headers may need to define it
149// externally.
150#if defined(OPENSSL_64_BIT)
151#define BN_ULONG uint64_t
152#define BN_BITS2 64
153#define BN_DEC_FMT1 "%" PRIu64
154#define BN_DEC_FMT2 "%019" PRIu64
155#define BN_HEX_FMT1 "%" PRIx64
156#define BN_HEX_FMT2 "%016" PRIx64
157#elif defined(OPENSSL_32_BIT)
158#define BN_ULONG uint32_t
159#define BN_BITS2 32
160#define BN_DEC_FMT1 "%" PRIu32
161#define BN_DEC_FMT2 "%09" PRIu32
162#define BN_HEX_FMT1 "%" PRIx32
163#define BN_HEX_FMT2 "%08" PRIx32
164#else
165#error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
166#endif
167
168
169// Allocation and freeing.
170
171// BN_new creates a new, allocated BIGNUM and initialises it.
172OPENSSL_EXPORT BIGNUM *BN_new(void);
173
174// BN_init initialises a stack allocated |BIGNUM|.
175OPENSSL_EXPORT void BN_init(BIGNUM *bn);
176
177// BN_free frees the data referenced by |bn| and, if |bn| was originally
178// allocated on the heap, frees |bn| also.
179OPENSSL_EXPORT void BN_free(BIGNUM *bn);
180
181// BN_clear_free erases and frees the data referenced by |bn| and, if |bn| was
182// originally allocated on the heap, frees |bn| also.
183OPENSSL_EXPORT void BN_clear_free(BIGNUM *bn);
184
185// BN_dup allocates a new BIGNUM and sets it equal to |src|. It returns the
186// allocated BIGNUM on success or NULL otherwise.
187OPENSSL_EXPORT BIGNUM *BN_dup(const BIGNUM *src);
188
189// BN_copy sets |dest| equal to |src| and returns |dest| or NULL on allocation
190// failure.
191OPENSSL_EXPORT BIGNUM *BN_copy(BIGNUM *dest, const BIGNUM *src);
192
193// BN_clear sets |bn| to zero and erases the old data.
194OPENSSL_EXPORT void BN_clear(BIGNUM *bn);
195
196// BN_value_one returns a static BIGNUM with value 1.
197OPENSSL_EXPORT const BIGNUM *BN_value_one(void);
198
199
200// Basic functions.
201
202// BN_num_bits returns the minimum number of bits needed to represent the
203// absolute value of |bn|.
204OPENSSL_EXPORT unsigned BN_num_bits(const BIGNUM *bn);
205
206// BN_num_bytes returns the minimum number of bytes needed to represent the
207// absolute value of |bn|.
208OPENSSL_EXPORT unsigned BN_num_bytes(const BIGNUM *bn);
209
210// BN_zero sets |bn| to zero.
211OPENSSL_EXPORT void BN_zero(BIGNUM *bn);
212
213// BN_one sets |bn| to one. It returns one on success or zero on allocation
214// failure.
215OPENSSL_EXPORT int BN_one(BIGNUM *bn);
216
217// BN_set_word sets |bn| to |value|. It returns one on success or zero on
218// allocation failure.
219OPENSSL_EXPORT int BN_set_word(BIGNUM *bn, BN_ULONG value);
220
221// BN_set_u64 sets |bn| to |value|. It returns one on success or zero on
222// allocation failure.
223OPENSSL_EXPORT int BN_set_u64(BIGNUM *bn, uint64_t value);
224
225// BN_set_negative sets the sign of |bn|.
226OPENSSL_EXPORT void BN_set_negative(BIGNUM *bn, int sign);
227
228// BN_is_negative returns one if |bn| is negative and zero otherwise.
229OPENSSL_EXPORT int BN_is_negative(const BIGNUM *bn);
230
231
232// Conversion functions.
233
234// BN_bin2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
235// a big-endian number, and returns |ret|. If |ret| is NULL then a fresh
236// |BIGNUM| is allocated and returned. It returns NULL on allocation
237// failure.
238OPENSSL_EXPORT BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret);
239
240// BN_bn2bin serialises the absolute value of |in| to |out| as a big-endian
241// integer, which must have |BN_num_bytes| of space available. It returns the
242// number of bytes written. Note this function leaks the magnitude of |in|. If
243// |in| is secret, use |BN_bn2bin_padded| instead.
244OPENSSL_EXPORT size_t BN_bn2bin(const BIGNUM *in, uint8_t *out);
245
246// BN_le2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
247// a little-endian number, and returns |ret|. If |ret| is NULL then a fresh
248// |BIGNUM| is allocated and returned. It returns NULL on allocation
249// failure.
250OPENSSL_EXPORT BIGNUM *BN_le2bn(const uint8_t *in, size_t len, BIGNUM *ret);
251
252// BN_bn2le_padded serialises the absolute value of |in| to |out| as a
253// little-endian integer, which must have |len| of space available, padding
254// out the remainder of out with zeros. If |len| is smaller than |BN_num_bytes|,
255// the function fails and returns 0. Otherwise, it returns 1.
256OPENSSL_EXPORT int BN_bn2le_padded(uint8_t *out, size_t len, const BIGNUM *in);
257
258// BN_bn2bin_padded serialises the absolute value of |in| to |out| as a
259// big-endian integer. The integer is padded with leading zeros up to size
260// |len|. If |len| is smaller than |BN_num_bytes|, the function fails and
261// returns 0. Otherwise, it returns 1.
262OPENSSL_EXPORT int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in);
263
264// BN_bn2cbb_padded behaves like |BN_bn2bin_padded| but writes to a |CBB|.
265OPENSSL_EXPORT int BN_bn2cbb_padded(CBB *out, size_t len, const BIGNUM *in);
266
267// BN_bn2hex returns an allocated string that contains a NUL-terminated, hex
268// representation of |bn|. If |bn| is negative, the first char in the resulting
269// string will be '-'. Returns NULL on allocation failure.
270OPENSSL_EXPORT char *BN_bn2hex(const BIGNUM *bn);
271
272// BN_hex2bn parses the leading hex number from |in|, which may be proceeded by
273// a '-' to indicate a negative number and may contain trailing, non-hex data.
274// If |outp| is not NULL, it constructs a BIGNUM equal to the hex number and
275// stores it in |*outp|. If |*outp| is NULL then it allocates a new BIGNUM and
276// updates |*outp|. It returns the number of bytes of |in| processed or zero on
277// error.
278OPENSSL_EXPORT int BN_hex2bn(BIGNUM **outp, const char *in);
279
280// BN_bn2dec returns an allocated string that contains a NUL-terminated,
281// decimal representation of |bn|. If |bn| is negative, the first char in the
282// resulting string will be '-'. Returns NULL on allocation failure.
283OPENSSL_EXPORT char *BN_bn2dec(const BIGNUM *a);
284
285// BN_dec2bn parses the leading decimal number from |in|, which may be
286// proceeded by a '-' to indicate a negative number and may contain trailing,
287// non-decimal data. If |outp| is not NULL, it constructs a BIGNUM equal to the
288// decimal number and stores it in |*outp|. If |*outp| is NULL then it
289// allocates a new BIGNUM and updates |*outp|. It returns the number of bytes
290// of |in| processed or zero on error.
291OPENSSL_EXPORT int BN_dec2bn(BIGNUM **outp, const char *in);
292
293// BN_asc2bn acts like |BN_dec2bn| or |BN_hex2bn| depending on whether |in|
294// begins with "0X" or "0x" (indicating hex) or not (indicating decimal). A
295// leading '-' is still permitted and comes before the optional 0X/0x. It
296// returns one on success or zero on error.
297OPENSSL_EXPORT int BN_asc2bn(BIGNUM **outp, const char *in);
298
299// BN_print writes a hex encoding of |a| to |bio|. It returns one on success
300// and zero on error.
301OPENSSL_EXPORT int BN_print(BIO *bio, const BIGNUM *a);
302
303// BN_print_fp acts like |BIO_print|, but wraps |fp| in a |BIO| first.
304OPENSSL_EXPORT int BN_print_fp(FILE *fp, const BIGNUM *a);
305
306// BN_get_word returns the absolute value of |bn| as a single word. If |bn| is
307// too large to be represented as a single word, the maximum possible value
308// will be returned.
309OPENSSL_EXPORT BN_ULONG BN_get_word(const BIGNUM *bn);
310
311// BN_get_u64 sets |*out| to the absolute value of |bn| as a |uint64_t| and
312// returns one. If |bn| is too large to be represented as a |uint64_t|, it
313// returns zero.
314OPENSSL_EXPORT int BN_get_u64(const BIGNUM *bn, uint64_t *out);
315
316
317// ASN.1 functions.
318
319// BN_parse_asn1_unsigned parses a non-negative DER INTEGER from |cbs| writes
320// the result to |ret|. It returns one on success and zero on failure.
321OPENSSL_EXPORT int BN_parse_asn1_unsigned(CBS *cbs, BIGNUM *ret);
322
323// BN_marshal_asn1 marshals |bn| as a non-negative DER INTEGER and appends the
324// result to |cbb|. It returns one on success and zero on failure.
325OPENSSL_EXPORT int BN_marshal_asn1(CBB *cbb, const BIGNUM *bn);
326
327
328// BIGNUM pools.
329//
330// Certain BIGNUM operations need to use many temporary variables and
331// allocating and freeing them can be quite slow. Thus such operations typically
332// take a |BN_CTX| parameter, which contains a pool of |BIGNUMs|. The |ctx|
333// argument to a public function may be NULL, in which case a local |BN_CTX|
334// will be created just for the lifetime of that call.
335//
336// A function must call |BN_CTX_start| first. Then, |BN_CTX_get| may be called
337// repeatedly to obtain temporary |BIGNUM|s. All |BN_CTX_get| calls must be made
338// before calling any other functions that use the |ctx| as an argument.
339//
340// Finally, |BN_CTX_end| must be called before returning from the function.
341// When |BN_CTX_end| is called, the |BIGNUM| pointers obtained from
342// |BN_CTX_get| become invalid.
343
344// BN_CTX_new returns a new, empty BN_CTX or NULL on allocation failure.
345OPENSSL_EXPORT BN_CTX *BN_CTX_new(void);
346
347// BN_CTX_free frees all BIGNUMs contained in |ctx| and then frees |ctx|
348// itself.
349OPENSSL_EXPORT void BN_CTX_free(BN_CTX *ctx);
350
351// BN_CTX_start "pushes" a new entry onto the |ctx| stack and allows future
352// calls to |BN_CTX_get|.
353OPENSSL_EXPORT void BN_CTX_start(BN_CTX *ctx);
354
355// BN_CTX_get returns a new |BIGNUM|, or NULL on allocation failure. Once
356// |BN_CTX_get| has returned NULL, all future calls will also return NULL until
357// |BN_CTX_end| is called.
358OPENSSL_EXPORT BIGNUM *BN_CTX_get(BN_CTX *ctx);
359
360// BN_CTX_end invalidates all |BIGNUM|s returned from |BN_CTX_get| since the
361// matching |BN_CTX_start| call.
362OPENSSL_EXPORT void BN_CTX_end(BN_CTX *ctx);
363
364
365// Simple arithmetic
366
367// BN_add sets |r| = |a| + |b|, where |r| may be the same pointer as either |a|
368// or |b|. It returns one on success and zero on allocation failure.
369OPENSSL_EXPORT int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
370
371// BN_uadd sets |r| = |a| + |b|, where |a| and |b| are non-negative and |r| may
372// be the same pointer as either |a| or |b|. It returns one on success and zero
373// on allocation failure.
374OPENSSL_EXPORT int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
375
376// BN_add_word adds |w| to |a|. It returns one on success and zero otherwise.
377OPENSSL_EXPORT int BN_add_word(BIGNUM *a, BN_ULONG w);
378
379// BN_sub sets |r| = |a| - |b|, where |r| may be the same pointer as either |a|
380// or |b|. It returns one on success and zero on allocation failure.
381OPENSSL_EXPORT int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
382
383// BN_usub sets |r| = |a| - |b|, where |a| and |b| are non-negative integers,
384// |b| < |a| and |r| may be the same pointer as either |a| or |b|. It returns
385// one on success and zero on allocation failure.
386OPENSSL_EXPORT int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
387
388// BN_sub_word subtracts |w| from |a|. It returns one on success and zero on
389// allocation failure.
390OPENSSL_EXPORT int BN_sub_word(BIGNUM *a, BN_ULONG w);
391
392// BN_mul sets |r| = |a| * |b|, where |r| may be the same pointer as |a| or
393// |b|. Returns one on success and zero otherwise.
394OPENSSL_EXPORT int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
395 BN_CTX *ctx);
396
397// BN_mul_word sets |bn| = |bn| * |w|. It returns one on success or zero on
398// allocation failure.
399OPENSSL_EXPORT int BN_mul_word(BIGNUM *bn, BN_ULONG w);
400
401// BN_sqr sets |r| = |a|^2 (i.e. squares), where |r| may be the same pointer as
402// |a|. Returns one on success and zero otherwise. This is more efficient than
403// BN_mul(r, a, a, ctx).
404OPENSSL_EXPORT int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx);
405
406// BN_div divides |numerator| by |divisor| and places the result in |quotient|
407// and the remainder in |rem|. Either of |quotient| or |rem| may be NULL, in
408// which case the respective value is not returned. The result is rounded
409// towards zero; thus if |numerator| is negative, the remainder will be zero or
410// negative. It returns one on success or zero on error.
411OPENSSL_EXPORT int BN_div(BIGNUM *quotient, BIGNUM *rem,
412 const BIGNUM *numerator, const BIGNUM *divisor,
413 BN_CTX *ctx);
414
415// BN_div_word sets |numerator| = |numerator|/|divisor| and returns the
416// remainder or (BN_ULONG)-1 on error.
417OPENSSL_EXPORT BN_ULONG BN_div_word(BIGNUM *numerator, BN_ULONG divisor);
418
419// BN_sqrt sets |*out_sqrt| (which may be the same |BIGNUM| as |in|) to the
420// square root of |in|, using |ctx|. It returns one on success or zero on
421// error. Negative numbers and non-square numbers will result in an error with
422// appropriate errors on the error queue.
423OPENSSL_EXPORT int BN_sqrt(BIGNUM *out_sqrt, const BIGNUM *in, BN_CTX *ctx);
424
425
426// Comparison functions
427
428// BN_cmp returns a value less than, equal to or greater than zero if |a| is
429// less than, equal to or greater than |b|, respectively.
430OPENSSL_EXPORT int BN_cmp(const BIGNUM *a, const BIGNUM *b);
431
432// BN_cmp_word is like |BN_cmp| except it takes its second argument as a
433// |BN_ULONG| instead of a |BIGNUM|.
434OPENSSL_EXPORT int BN_cmp_word(const BIGNUM *a, BN_ULONG b);
435
436// BN_ucmp returns a value less than, equal to or greater than zero if the
437// absolute value of |a| is less than, equal to or greater than the absolute
438// value of |b|, respectively.
439OPENSSL_EXPORT int BN_ucmp(const BIGNUM *a, const BIGNUM *b);
440
441// BN_equal_consttime returns one if |a| is equal to |b|, and zero otherwise.
442// It takes an amount of time dependent on the sizes of |a| and |b|, but
443// independent of the contents (including the signs) of |a| and |b|.
444OPENSSL_EXPORT int BN_equal_consttime(const BIGNUM *a, const BIGNUM *b);
445
446// BN_abs_is_word returns one if the absolute value of |bn| equals |w| and zero
447// otherwise.
448OPENSSL_EXPORT int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w);
449
450// BN_is_zero returns one if |bn| is zero and zero otherwise.
451OPENSSL_EXPORT int BN_is_zero(const BIGNUM *bn);
452
453// BN_is_one returns one if |bn| equals one and zero otherwise.
454OPENSSL_EXPORT int BN_is_one(const BIGNUM *bn);
455
456// BN_is_word returns one if |bn| is exactly |w| and zero otherwise.
457OPENSSL_EXPORT int BN_is_word(const BIGNUM *bn, BN_ULONG w);
458
459// BN_is_odd returns one if |bn| is odd and zero otherwise.
460OPENSSL_EXPORT int BN_is_odd(const BIGNUM *bn);
461
462// BN_is_pow2 returns 1 if |a| is a power of two, and 0 otherwise.
463OPENSSL_EXPORT int BN_is_pow2(const BIGNUM *a);
464
465
466// Bitwise operations.
467
468// BN_lshift sets |r| equal to |a| << n. The |a| and |r| arguments may be the
469// same |BIGNUM|. It returns one on success and zero on allocation failure.
470OPENSSL_EXPORT int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
471
472// BN_lshift1 sets |r| equal to |a| << 1, where |r| and |a| may be the same
473// pointer. It returns one on success and zero on allocation failure.
474OPENSSL_EXPORT int BN_lshift1(BIGNUM *r, const BIGNUM *a);
475
476// BN_rshift sets |r| equal to |a| >> n, where |r| and |a| may be the same
477// pointer. It returns one on success and zero on allocation failure.
478OPENSSL_EXPORT int BN_rshift(BIGNUM *r, const BIGNUM *a, int n);
479
480// BN_rshift1 sets |r| equal to |a| >> 1, where |r| and |a| may be the same
481// pointer. It returns one on success and zero on allocation failure.
482OPENSSL_EXPORT int BN_rshift1(BIGNUM *r, const BIGNUM *a);
483
484// BN_set_bit sets the |n|th, least-significant bit in |a|. For example, if |a|
485// is 2 then setting bit zero will make it 3. It returns one on success or zero
486// on allocation failure.
487OPENSSL_EXPORT int BN_set_bit(BIGNUM *a, int n);
488
489// BN_clear_bit clears the |n|th, least-significant bit in |a|. For example, if
490// |a| is 3, clearing bit zero will make it two. It returns one on success or
491// zero on allocation failure.
492OPENSSL_EXPORT int BN_clear_bit(BIGNUM *a, int n);
493
494// BN_is_bit_set returns one if the |n|th least-significant bit in |a| exists
495// and is set. Otherwise, it returns zero.
496OPENSSL_EXPORT int BN_is_bit_set(const BIGNUM *a, int n);
497
498// BN_mask_bits truncates |a| so that it is only |n| bits long. It returns one
499// on success or zero if |n| is negative.
500//
501// This differs from OpenSSL which additionally returns zero if |a|'s word
502// length is less than or equal to |n|, rounded down to a number of words. Note
503// word size is platform-dependent, so this behavior is also difficult to rely
504// on in OpenSSL and not very useful.
505OPENSSL_EXPORT int BN_mask_bits(BIGNUM *a, int n);
506
507// BN_count_low_zero_bits returns the number of low-order zero bits in |bn|, or
508// the number of factors of two which divide it. It returns zero if |bn| is
509// zero.
510OPENSSL_EXPORT int BN_count_low_zero_bits(const BIGNUM *bn);
511
512
513// Modulo arithmetic.
514
515// BN_mod_word returns |a| mod |w| or (BN_ULONG)-1 on error.
516OPENSSL_EXPORT BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
517
518// BN_mod_pow2 sets |r| = |a| mod 2^|e|. It returns 1 on success and
519// 0 on error.
520OPENSSL_EXPORT int BN_mod_pow2(BIGNUM *r, const BIGNUM *a, size_t e);
521
522// BN_nnmod_pow2 sets |r| = |a| mod 2^|e| where |r| is always positive.
523// It returns 1 on success and 0 on error.
524OPENSSL_EXPORT int BN_nnmod_pow2(BIGNUM *r, const BIGNUM *a, size_t e);
525
526// BN_mod is a helper macro that calls |BN_div| and discards the quotient.
527#define BN_mod(rem, numerator, divisor, ctx) \
528 BN_div(NULL, (rem), (numerator), (divisor), (ctx))
529
530// BN_nnmod is a non-negative modulo function. It acts like |BN_mod|, but 0 <=
531// |rem| < |divisor| is always true. It returns one on success and zero on
532// error.
533OPENSSL_EXPORT int BN_nnmod(BIGNUM *rem, const BIGNUM *numerator,
534 const BIGNUM *divisor, BN_CTX *ctx);
535
536// BN_mod_add sets |r| = |a| + |b| mod |m|. It returns one on success and zero
537// on error.
538OPENSSL_EXPORT int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
539 const BIGNUM *m, BN_CTX *ctx);
540
541// BN_mod_add_quick acts like |BN_mod_add| but requires that |a| and |b| be
542// non-negative and less than |m|.
543OPENSSL_EXPORT int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
544 const BIGNUM *m);
545
546// BN_mod_sub sets |r| = |a| - |b| mod |m|. It returns one on success and zero
547// on error.
548OPENSSL_EXPORT int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
549 const BIGNUM *m, BN_CTX *ctx);
550
551// BN_mod_sub_quick acts like |BN_mod_sub| but requires that |a| and |b| be
552// non-negative and less than |m|.
553OPENSSL_EXPORT int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
554 const BIGNUM *m);
555
556// BN_mod_mul sets |r| = |a|*|b| mod |m|. It returns one on success and zero
557// on error.
558OPENSSL_EXPORT int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
559 const BIGNUM *m, BN_CTX *ctx);
560
561// BN_mod_sqr sets |r| = |a|^2 mod |m|. It returns one on success and zero
562// on error.
563OPENSSL_EXPORT int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
564 BN_CTX *ctx);
565
566// BN_mod_lshift sets |r| = (|a| << n) mod |m|, where |r| and |a| may be the
567// same pointer. It returns one on success and zero on error.
568OPENSSL_EXPORT int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n,
569 const BIGNUM *m, BN_CTX *ctx);
570
571// BN_mod_lshift_quick acts like |BN_mod_lshift| but requires that |a| be
572// non-negative and less than |m|.
573OPENSSL_EXPORT int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n,
574 const BIGNUM *m);
575
576// BN_mod_lshift1 sets |r| = (|a| << 1) mod |m|, where |r| and |a| may be the
577// same pointer. It returns one on success and zero on error.
578OPENSSL_EXPORT int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
579 BN_CTX *ctx);
580
581// BN_mod_lshift1_quick acts like |BN_mod_lshift1| but requires that |a| be
582// non-negative and less than |m|.
583OPENSSL_EXPORT int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a,
584 const BIGNUM *m);
585
586// BN_mod_sqrt returns a newly-allocated |BIGNUM|, r, such that
587// r^2 == a (mod p). |p| must be a prime. It returns NULL on error or if |a| is
588// not a square mod |p|. In the latter case, it will add |BN_R_NOT_A_SQUARE| to
589// the error queue.
590OPENSSL_EXPORT BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p,
591 BN_CTX *ctx);
592
593
594// Random and prime number generation.
595
596// The following are values for the |top| parameter of |BN_rand|.
597#define BN_RAND_TOP_ANY (-1)
598#define BN_RAND_TOP_ONE 0
599#define BN_RAND_TOP_TWO 1
600
601// The following are values for the |bottom| parameter of |BN_rand|.
602#define BN_RAND_BOTTOM_ANY 0
603#define BN_RAND_BOTTOM_ODD 1
604
605// BN_rand sets |rnd| to a random number of length |bits|. It returns one on
606// success and zero otherwise.
607//
608// |top| must be one of the |BN_RAND_TOP_*| values. If |BN_RAND_TOP_ONE|, the
609// most-significant bit, if any, will be set. If |BN_RAND_TOP_TWO|, the two
610// most significant bits, if any, will be set. If |BN_RAND_TOP_ANY|, no extra
611// action will be taken and |BN_num_bits(rnd)| may not equal |bits| if the most
612// significant bits randomly ended up as zeros.
613//
614// |bottom| must be one of the |BN_RAND_BOTTOM_*| values. If
615// |BN_RAND_BOTTOM_ODD|, the least-significant bit, if any, will be set. If
616// |BN_RAND_BOTTOM_ANY|, no extra action will be taken.
617OPENSSL_EXPORT int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
618
619// BN_pseudo_rand is an alias for |BN_rand|.
620OPENSSL_EXPORT int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
621
622// BN_rand_range is equivalent to |BN_rand_range_ex| with |min_inclusive| set
623// to zero and |max_exclusive| set to |range|.
624OPENSSL_EXPORT int BN_rand_range(BIGNUM *rnd, const BIGNUM *range);
625
626// BN_rand_range_ex sets |rnd| to a random value in
627// [min_inclusive..max_exclusive). It returns one on success and zero
628// otherwise.
629OPENSSL_EXPORT int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive,
630 const BIGNUM *max_exclusive);
631
632// BN_pseudo_rand_range is an alias for BN_rand_range.
633OPENSSL_EXPORT int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range);
634
635#define BN_GENCB_GENERATED 0
636#define BN_GENCB_PRIME_TEST 1
637
638// bn_gencb_st, or |BN_GENCB|, holds a callback function that is used by
639// generation functions that can take a very long time to complete. Use
640// |BN_GENCB_set| to initialise a |BN_GENCB| structure.
641//
642// The callback receives the address of that |BN_GENCB| structure as its last
643// argument and the user is free to put an arbitrary pointer in |arg|. The other
644// arguments are set as follows:
645// event=BN_GENCB_GENERATED, n=i: after generating the i'th possible prime
646// number.
647// event=BN_GENCB_PRIME_TEST, n=-1: when finished trial division primality
648// checks.
649// event=BN_GENCB_PRIME_TEST, n=i: when the i'th primality test has finished.
650//
651// The callback can return zero to abort the generation progress or one to
652// allow it to continue.
653//
654// When other code needs to call a BN generation function it will often take a
655// BN_GENCB argument and may call the function with other argument values.
656struct bn_gencb_st {
657 void *arg; // callback-specific data
658 int (*callback)(int event, int n, struct bn_gencb_st *);
659};
660
661// BN_GENCB_set configures |callback| to call |f| and sets |callout->arg| to
662// |arg|.
663OPENSSL_EXPORT void BN_GENCB_set(BN_GENCB *callback,
664 int (*f)(int event, int n, BN_GENCB *),
665 void *arg);
666
667// BN_GENCB_call calls |callback|, if not NULL, and returns the return value of
668// the callback, or 1 if |callback| is NULL.
669OPENSSL_EXPORT int BN_GENCB_call(BN_GENCB *callback, int event, int n);
670
671// BN_generate_prime_ex sets |ret| to a prime number of |bits| length. If safe
672// is non-zero then the prime will be such that (ret-1)/2 is also a prime.
673// (This is needed for Diffie-Hellman groups to ensure that the only subgroups
674// are of size 2 and (p-1)/2.).
675//
676// If |add| is not NULL, the prime will fulfill the condition |ret| % |add| ==
677// |rem| in order to suit a given generator. (If |rem| is NULL then |ret| %
678// |add| == 1.)
679//
680// If |cb| is not NULL, it will be called during processing to give an
681// indication of progress. See the comments for |BN_GENCB|. It returns one on
682// success and zero otherwise.
683OPENSSL_EXPORT int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
684 const BIGNUM *add, const BIGNUM *rem,
685 BN_GENCB *cb);
686
687// BN_prime_checks is magic value that can be used as the |checks| argument to
688// the primality testing functions in order to automatically select a number of
689// Miller-Rabin checks that gives a false positive rate of ~2^{-80}.
690#define BN_prime_checks 0
691
692// bn_primality_result_t enumerates the outcomes of primality-testing.
693enum bn_primality_result_t {
694 bn_probably_prime,
695 bn_composite,
696 bn_non_prime_power_composite,
697};
698
699// BN_enhanced_miller_rabin_primality_test tests whether |w| is probably a prime
700// number using the Enhanced Miller-Rabin Test (FIPS 186-4 C.3.2) with
701// |iterations| iterations and returns the result in |out_result|. Enhanced
702// Miller-Rabin tests primality for odd integers greater than 3, returning
703// |bn_probably_prime| if the number is probably prime,
704// |bn_non_prime_power_composite| if the number is a composite that is not the
705// power of a single prime, and |bn_composite| otherwise. It returns one on
706// success and zero on failure. If |cb| is not NULL, then it is called during
707// each iteration of the primality test.
708//
709// If |iterations| is |BN_prime_checks|, then a value that results in a false
710// positive rate lower than the number-field sieve security level of |w| is
711// used, provided |w| was generated randomly. |BN_prime_checks| is not suitable
712// for inputs potentially crafted by an adversary.
713OPENSSL_EXPORT int BN_enhanced_miller_rabin_primality_test(
714 enum bn_primality_result_t *out_result, const BIGNUM *w, int iterations,
715 BN_CTX *ctx, BN_GENCB *cb);
716
717// BN_primality_test sets |*is_probably_prime| to one if |candidate| is
718// probably a prime number by the Miller-Rabin test or zero if it's certainly
719// not.
720//
721// If |do_trial_division| is non-zero then |candidate| will be tested against a
722// list of small primes before Miller-Rabin tests. The probability of this
723// function returning a false positive is 2^{2*checks}. If |checks| is
724// |BN_prime_checks| then a value that results in a false positive rate lower
725// than the number-field sieve security level of |candidate| is used, provided
726// |candidate| was generated randomly. |BN_prime_checks| is not suitable for
727// inputs potentially crafted by an adversary.
728//
729// If |cb| is not NULL then it is called during the checking process. See the
730// comment above |BN_GENCB|.
731//
732// The function returns one on success and zero on error.
733OPENSSL_EXPORT int BN_primality_test(int *is_probably_prime,
734 const BIGNUM *candidate, int checks,
735 BN_CTX *ctx, int do_trial_division,
736 BN_GENCB *cb);
737
738// BN_is_prime_fasttest_ex returns one if |candidate| is probably a prime
739// number by the Miller-Rabin test, zero if it's certainly not and -1 on error.
740//
741// If |do_trial_division| is non-zero then |candidate| will be tested against a
742// list of small primes before Miller-Rabin tests. The probability of this
743// function returning one when |candidate| is composite is 2^{2*checks}. If
744// |checks| is |BN_prime_checks| then a value that results in a false positive
745// rate lower than the number-field sieve security level of |candidate| is used,
746// provided |candidate| was generated randomly. |BN_prime_checks| is not
747// suitable for inputs potentially crafted by an adversary.
748//
749// If |cb| is not NULL then it is called during the checking process. See the
750// comment above |BN_GENCB|.
751//
752// WARNING: deprecated. Use |BN_primality_test|.
753OPENSSL_EXPORT int BN_is_prime_fasttest_ex(const BIGNUM *candidate, int checks,
754 BN_CTX *ctx, int do_trial_division,
755 BN_GENCB *cb);
756
757// BN_is_prime_ex acts the same as |BN_is_prime_fasttest_ex| with
758// |do_trial_division| set to zero.
759//
760// WARNING: deprecated: Use |BN_primality_test|.
761OPENSSL_EXPORT int BN_is_prime_ex(const BIGNUM *candidate, int checks,
762 BN_CTX *ctx, BN_GENCB *cb);
763
764
765// Number theory functions
766
767// BN_gcd sets |r| = gcd(|a|, |b|). It returns one on success and zero
768// otherwise.
769OPENSSL_EXPORT int BN_gcd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
770 BN_CTX *ctx);
771
772// BN_mod_inverse sets |out| equal to |a|^-1, mod |n|. If |out| is NULL, a
773// fresh BIGNUM is allocated. It returns the result or NULL on error.
774//
775// If |n| is even then the operation is performed using an algorithm that avoids
776// some branches but which isn't constant-time. This function shouldn't be used
777// for secret values; use |BN_mod_inverse_blinded| instead. Or, if |n| is
778// guaranteed to be prime, use
779// |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
780// advantage of Fermat's Little Theorem.
781OPENSSL_EXPORT BIGNUM *BN_mod_inverse(BIGNUM *out, const BIGNUM *a,
782 const BIGNUM *n, BN_CTX *ctx);
783
784// BN_mod_inverse_blinded sets |out| equal to |a|^-1, mod |n|, where |n| is the
785// Montgomery modulus for |mont|. |a| must be non-negative and must be less
786// than |n|. |n| must be greater than 1. |a| is blinded (masked by a random
787// value) to protect it against side-channel attacks. On failure, if the failure
788// was caused by |a| having no inverse mod |n| then |*out_no_inverse| will be
789// set to one; otherwise it will be set to zero.
790//
791// Note this function may incorrectly report |a| has no inverse if the random
792// blinding value has no inverse. It should only be used when |n| has few
793// non-invertible elements, such as an RSA modulus.
794int BN_mod_inverse_blinded(BIGNUM *out, int *out_no_inverse, const BIGNUM *a,
795 const BN_MONT_CTX *mont, BN_CTX *ctx);
796
797// BN_mod_inverse_odd sets |out| equal to |a|^-1, mod |n|. |a| must be
798// non-negative and must be less than |n|. |n| must be odd. This function
799// shouldn't be used for secret values; use |BN_mod_inverse_blinded| instead.
800// Or, if |n| is guaranteed to be prime, use
801// |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
802// advantage of Fermat's Little Theorem. It returns one on success or zero on
803// failure. On failure, if the failure was caused by |a| having no inverse mod
804// |n| then |*out_no_inverse| will be set to one; otherwise it will be set to
805// zero.
806int BN_mod_inverse_odd(BIGNUM *out, int *out_no_inverse, const BIGNUM *a,
807 const BIGNUM *n, BN_CTX *ctx);
808
809
810// Montgomery arithmetic.
811
812// BN_MONT_CTX contains the precomputed values needed to work in a specific
813// Montgomery domain.
814
815// BN_MONT_CTX_new_for_modulus returns a fresh |BN_MONT_CTX| given the modulus,
816// |mod| or NULL on error. Note this function assumes |mod| is public.
817OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new_for_modulus(const BIGNUM *mod,
818 BN_CTX *ctx);
819
820// BN_MONT_CTX_new_consttime behaves like |BN_MONT_CTX_new_for_modulus| but
821// treats |mod| as secret.
822OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new_consttime(const BIGNUM *mod,
823 BN_CTX *ctx);
824
825// BN_MONT_CTX_free frees memory associated with |mont|.
826OPENSSL_EXPORT void BN_MONT_CTX_free(BN_MONT_CTX *mont);
827
828// BN_MONT_CTX_copy sets |to| equal to |from|. It returns |to| on success or
829// NULL on error.
830OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to,
831 const BN_MONT_CTX *from);
832
833// BN_MONT_CTX_set_locked takes |lock| and checks whether |*pmont| is NULL. If
834// so, it creates a new |BN_MONT_CTX| and sets the modulus for it to |mod|. It
835// then stores it as |*pmont|. It returns one on success and zero on error. Note
836// this function assumes |mod| is public.
837//
838// If |*pmont| is already non-NULL then it does nothing and returns one.
839int BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_MUTEX *lock,
840 const BIGNUM *mod, BN_CTX *bn_ctx);
841
842// BN_to_montgomery sets |ret| equal to |a| in the Montgomery domain. |a| is
843// assumed to be in the range [0, n), where |n| is the Montgomery modulus. It
844// returns one on success or zero on error.
845OPENSSL_EXPORT int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a,
846 const BN_MONT_CTX *mont, BN_CTX *ctx);
847
848// BN_from_montgomery sets |ret| equal to |a| * R^-1, i.e. translates values out
849// of the Montgomery domain. |a| is assumed to be in the range [0, n), where |n|
850// is the Montgomery modulus. It returns one on success or zero on error.
851OPENSSL_EXPORT int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a,
852 const BN_MONT_CTX *mont, BN_CTX *ctx);
853
854// BN_mod_mul_montgomery set |r| equal to |a| * |b|, in the Montgomery domain.
855// Both |a| and |b| must already be in the Montgomery domain (by
856// |BN_to_montgomery|). In particular, |a| and |b| are assumed to be in the
857// range [0, n), where |n| is the Montgomery modulus. It returns one on success
858// or zero on error.
859OPENSSL_EXPORT int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a,
860 const BIGNUM *b,
861 const BN_MONT_CTX *mont, BN_CTX *ctx);
862
863
864// Exponentiation.
865
866// BN_exp sets |r| equal to |a|^{|p|}. It does so with a square-and-multiply
867// algorithm that leaks side-channel information. It returns one on success or
868// zero otherwise.
869OPENSSL_EXPORT int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
870 BN_CTX *ctx);
871
872// BN_mod_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
873// algorithm for the values provided. It returns one on success or zero
874// otherwise. The |BN_mod_exp_mont_consttime| variant must be used if the
875// exponent is secret.
876OPENSSL_EXPORT int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
877 const BIGNUM *m, BN_CTX *ctx);
878
879// BN_mod_exp_mont behaves like |BN_mod_exp| but treats |a| as secret and
880// requires 0 <= |a| < |m|.
881OPENSSL_EXPORT int BN_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
882 const BIGNUM *m, BN_CTX *ctx,
883 const BN_MONT_CTX *mont);
884
885// BN_mod_exp_mont_consttime behaves like |BN_mod_exp| but treats |a|, |p|, and
886// |m| as secret and requires 0 <= |a| < |m|.
887OPENSSL_EXPORT int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a,
888 const BIGNUM *p, const BIGNUM *m,
889 BN_CTX *ctx,
890 const BN_MONT_CTX *mont);
891
892
893// Deprecated functions
894
895// BN_bn2mpi serialises the value of |in| to |out|, using a format that consists
896// of the number's length in bytes represented as a 4-byte big-endian number,
897// and the number itself in big-endian format, where the most significant bit
898// signals a negative number. (The representation of numbers with the MSB set is
899// prefixed with null byte). |out| must have sufficient space available; to
900// find the needed amount of space, call the function with |out| set to NULL.
901OPENSSL_EXPORT size_t BN_bn2mpi(const BIGNUM *in, uint8_t *out);
902
903// BN_mpi2bn parses |len| bytes from |in| and returns the resulting value. The
904// bytes at |in| are expected to be in the format emitted by |BN_bn2mpi|.
905//
906// If |out| is NULL then a fresh |BIGNUM| is allocated and returned, otherwise
907// |out| is reused and returned. On error, NULL is returned and the error queue
908// is updated.
909OPENSSL_EXPORT BIGNUM *BN_mpi2bn(const uint8_t *in, size_t len, BIGNUM *out);
910
911// BN_mod_exp_mont_word is like |BN_mod_exp_mont| except that the base |a| is
912// given as a |BN_ULONG| instead of a |BIGNUM *|. It returns one on success
913// or zero otherwise.
914OPENSSL_EXPORT int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
915 const BIGNUM *m, BN_CTX *ctx,
916 const BN_MONT_CTX *mont);
917
918// BN_mod_exp2_mont calculates (a1^p1) * (a2^p2) mod m. It returns 1 on success
919// or zero otherwise.
920OPENSSL_EXPORT int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1,
921 const BIGNUM *p1, const BIGNUM *a2,
922 const BIGNUM *p2, const BIGNUM *m,
923 BN_CTX *ctx, const BN_MONT_CTX *mont);
924
925// BN_MONT_CTX_new returns a fresh |BN_MONT_CTX| or NULL on allocation failure.
926// Use |BN_MONT_CTX_new_for_modulus| instead.
927OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new(void);
928
929// BN_MONT_CTX_set sets up a Montgomery context given the modulus, |mod|. It
930// returns one on success and zero on error. Use |BN_MONT_CTX_new_for_modulus|
931// instead.
932OPENSSL_EXPORT int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod,
933 BN_CTX *ctx);
934
935// BN_bn2binpad behaves like |BN_bn2bin_padded|, but it returns |len| on success
936// and -1 on error.
937//
938// Use |BN_bn2bin_padded| instead. It is |size_t|-clean.
939OPENSSL_EXPORT int BN_bn2binpad(const BIGNUM *in, uint8_t *out, int len);
940
941
942// Private functions
943
944struct bignum_st {
945 // d is a pointer to an array of |width| |BN_BITS2|-bit chunks in
946 // little-endian order. This stores the absolute value of the number.
947 BN_ULONG *d;
948 // width is the number of elements of |d| which are valid. This value is not
949 // necessarily minimal; the most-significant words of |d| may be zero.
950 // |width| determines a potentially loose upper-bound on the absolute value
951 // of the |BIGNUM|.
952 //
953 // Functions taking |BIGNUM| inputs must compute the same answer for all
954 // possible widths. |bn_minimal_width|, |bn_set_minimal_width|, and other
955 // helpers may be used to recover the minimal width, provided it is not
956 // secret. If it is secret, use a different algorithm. Functions may output
957 // minimal or non-minimal |BIGNUM|s depending on secrecy requirements, but
958 // those which cause widths to unboundedly grow beyond the minimal value
959 // should be documented such.
960 //
961 // Note this is different from historical |BIGNUM| semantics.
962 int width;
963 // dmax is number of elements of |d| which are allocated.
964 int dmax;
965 // neg is one if the number if negative and zero otherwise.
966 int neg;
967 // flags is a bitmask of |BN_FLG_*| values
968 int flags;
969};
970
971struct bn_mont_ctx_st {
972 // RR is R^2, reduced modulo |N|. It is used to convert to Montgomery form. It
973 // is guaranteed to have the same width as |N|.
974 BIGNUM RR;
975 // N is the modulus. It is always stored in minimal form, so |N.width|
976 // determines R.
977 BIGNUM N;
978 BN_ULONG n0[2]; // least significant words of (R*Ri-1)/N
979};
980
981OPENSSL_EXPORT unsigned BN_num_bits_word(BN_ULONG l);
982
983#define BN_FLG_MALLOCED 0x01
984#define BN_FLG_STATIC_DATA 0x02
985// |BN_FLG_CONSTTIME| has been removed and intentionally omitted so code relying
986// on it will not compile. Consumers outside BoringSSL should use the
987// higher-level cryptographic algorithms exposed by other modules. Consumers
988// within the library should call the appropriate timing-sensitive algorithm
989// directly.
990
991
992#if defined(__cplusplus)
993} // extern C
994
995#if !defined(BORINGSSL_NO_CXX)
996extern "C++" {
997
998BSSL_NAMESPACE_BEGIN
999
1000BORINGSSL_MAKE_DELETER(BIGNUM, BN_free)
1001BORINGSSL_MAKE_DELETER(BN_CTX, BN_CTX_free)
1002BORINGSSL_MAKE_DELETER(BN_MONT_CTX, BN_MONT_CTX_free)
1003
1004class BN_CTXScope {
1005 public:
1006 BN_CTXScope(BN_CTX *ctx) : ctx_(ctx) { BN_CTX_start(ctx_); }
1007 ~BN_CTXScope() { BN_CTX_end(ctx_); }
1008
1009 private:
1010 BN_CTX *ctx_;
1011
1012 BN_CTXScope(BN_CTXScope &) = delete;
1013 BN_CTXScope &operator=(BN_CTXScope &) = delete;
1014};
1015
1016BSSL_NAMESPACE_END
1017
1018} // extern C++
1019#endif
1020
1021#endif
1022
1023#define BN_R_ARG2_LT_ARG3 100
1024#define BN_R_BAD_RECIPROCAL 101
1025#define BN_R_BIGNUM_TOO_LONG 102
1026#define BN_R_BITS_TOO_SMALL 103
1027#define BN_R_CALLED_WITH_EVEN_MODULUS 104
1028#define BN_R_DIV_BY_ZERO 105
1029#define BN_R_EXPAND_ON_STATIC_BIGNUM_DATA 106
1030#define BN_R_INPUT_NOT_REDUCED 107
1031#define BN_R_INVALID_RANGE 108
1032#define BN_R_NEGATIVE_NUMBER 109
1033#define BN_R_NOT_A_SQUARE 110
1034#define BN_R_NOT_INITIALIZED 111
1035#define BN_R_NO_INVERSE 112
1036#define BN_R_PRIVATE_KEY_TOO_LARGE 113
1037#define BN_R_P_IS_NOT_PRIME 114
1038#define BN_R_TOO_MANY_ITERATIONS 115
1039#define BN_R_TOO_MANY_TEMPORARY_VARIABLES 116
1040#define BN_R_BAD_ENCODING 117
1041#define BN_R_ENCODE_ERROR 118
1042#define BN_R_INVALID_INPUT 119
1043
1044#endif // OPENSSL_HEADER_BN_H
1045