Mercurial > dropbear
comparison libtommath/bn_mp_reduce_2k.c @ 1655:f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
* make key-generation compliant to FIPS 186.4
* fix includes in tommath_class.h
* update fuzzcorpus instead of error-out
* fixup fuzzing make-targets
* update Makefile.in
* apply necessary patches to ltm sources
* clean-up not required ltm files
* update to vanilla ltm 1.1.0
this already only contains the required files
* remove set/get double
author | Steffen Jaeckel <s_jaeckel@gmx.de> |
---|---|
date | Mon, 16 Sep 2019 15:50:38 +0200 |
parents | 8bba51a55704 |
children | 1051e4eea25a |
comparison
equal
deleted
inserted
replaced
1654:cc0fc5131c5c | 1655:f52919ffd3b1 |
---|---|
1 #include <tommath_private.h> | 1 #include "tommath_private.h" |
2 #ifdef BN_MP_REDUCE_2K_C | 2 #ifdef BN_MP_REDUCE_2K_C |
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis | 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
4 * | 4 * |
5 * LibTomMath is a library that provides multiple-precision | 5 * LibTomMath is a library that provides multiple-precision |
6 * integer arithmetic as well as number theoretic functionality. | 6 * integer arithmetic as well as number theoretic functionality. |
7 * | 7 * |
8 * The library was designed directly after the MPI library by | 8 * The library was designed directly after the MPI library by |
9 * Michael Fromberger but has been written from scratch with | 9 * Michael Fromberger but has been written from scratch with |
10 * additional optimizations in place. | 10 * additional optimizations in place. |
11 * | 11 * |
12 * The library is free for all purposes without any express | 12 * SPDX-License-Identifier: Unlicense |
13 * guarantee it works. | |
14 * | |
15 * Tom St Denis, [email protected], http://libtom.org | |
16 */ | 13 */ |
17 | 14 |
18 /* reduces a modulo n where n is of the form 2**p - d */ | 15 /* reduces a modulo n where n is of the form 2**p - d */ |
19 int mp_reduce_2k(mp_int *a, mp_int *n, mp_digit d) | 16 int mp_reduce_2k(mp_int *a, const mp_int *n, mp_digit d) |
20 { | 17 { |
21 mp_int q; | 18 mp_int q; |
22 int p, res; | 19 int p, res; |
23 | 20 |
24 if ((res = mp_init(&q)) != MP_OKAY) { | 21 if ((res = mp_init(&q)) != MP_OKAY) { |
27 | 24 |
28 p = mp_count_bits(n); | 25 p = mp_count_bits(n); |
29 top: | 26 top: |
30 /* q = a/2**p, a = a mod 2**p */ | 27 /* q = a/2**p, a = a mod 2**p */ |
31 if ((res = mp_div_2d(a, p, &q, a)) != MP_OKAY) { | 28 if ((res = mp_div_2d(a, p, &q, a)) != MP_OKAY) { |
32 goto ERR; | 29 goto LBL_ERR; |
33 } | 30 } |
34 | 31 |
35 if (d != 1) { | 32 if (d != 1u) { |
36 /* q = q * d */ | 33 /* q = q * d */ |
37 if ((res = mp_mul_d(&q, d, &q)) != MP_OKAY) { | 34 if ((res = mp_mul_d(&q, d, &q)) != MP_OKAY) { |
38 goto ERR; | 35 goto LBL_ERR; |
39 } | 36 } |
40 } | 37 } |
41 | 38 |
42 /* a = a + q */ | 39 /* a = a + q */ |
43 if ((res = s_mp_add(a, &q, a)) != MP_OKAY) { | 40 if ((res = s_mp_add(a, &q, a)) != MP_OKAY) { |
44 goto ERR; | 41 goto LBL_ERR; |
45 } | 42 } |
46 | 43 |
47 if (mp_cmp_mag(a, n) != MP_LT) { | 44 if (mp_cmp_mag(a, n) != MP_LT) { |
48 if ((res = s_mp_sub(a, n, a)) != MP_OKAY) { | 45 if ((res = s_mp_sub(a, n, a)) != MP_OKAY) { |
49 goto ERR; | 46 goto LBL_ERR; |
50 } | 47 } |
51 goto top; | 48 goto top; |
52 } | 49 } |
53 | 50 |
54 ERR: | 51 LBL_ERR: |
55 mp_clear(&q); | 52 mp_clear(&q); |
56 return res; | 53 return res; |
57 } | 54 } |
58 | 55 |
59 #endif | 56 #endif |
60 | 57 |
61 /* ref: $Format:%D$ */ | 58 /* ref: HEAD -> master, tag: v1.1.0 */ |
62 /* git commit: $Format:%H$ */ | 59 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ |
63 /* commit time: $Format:%ai$ */ | 60 /* commit time: 2019-01-28 20:32:32 +0100 */ |