Mercurial > dropbear
comparison libtommath/bn_mp_expt_d_ex.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> |
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date | Mon, 16 Sep 2019 15:50:38 +0200 |
parents | 8bba51a55704 |
children |
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1654:cc0fc5131c5c | 1655:f52919ffd3b1 |
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1 #include <tommath_private.h> | 1 #include "tommath_private.h" |
2 #ifdef BN_MP_EXPT_D_EX_C | 2 #ifdef BN_MP_EXPT_D_EX_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 /* calculate c = a**b using a square-multiply algorithm */ | 15 /* calculate c = a**b using a square-multiply algorithm */ |
19 int mp_expt_d_ex (mp_int * a, mp_digit b, mp_int * c, int fast) | 16 int mp_expt_d_ex(const mp_int *a, mp_digit b, mp_int *c, int fast) |
20 { | 17 { |
21 int res; | 18 int res; |
22 unsigned int x; | 19 unsigned int x; |
23 | 20 |
24 mp_int g; | 21 mp_int g; |
25 | 22 |
26 if ((res = mp_init_copy (&g, a)) != MP_OKAY) { | 23 if ((res = mp_init_copy(&g, a)) != MP_OKAY) { |
27 return res; | 24 return res; |
28 } | 25 } |
29 | 26 |
30 /* set initial result */ | 27 /* set initial result */ |
31 mp_set (c, 1); | 28 mp_set(c, 1uL); |
32 | 29 |
33 if (fast != 0) { | 30 if (fast != 0) { |
34 while (b > 0) { | 31 while (b > 0u) { |
35 /* if the bit is set multiply */ | 32 /* if the bit is set multiply */ |
36 if ((b & 1) != 0) { | 33 if ((b & 1u) != 0u) { |
37 if ((res = mp_mul (c, &g, c)) != MP_OKAY) { | 34 if ((res = mp_mul(c, &g, c)) != MP_OKAY) { |
38 mp_clear (&g); | 35 mp_clear(&g); |
39 return res; | 36 return res; |
40 } | 37 } |
38 } | |
39 | |
40 /* square */ | |
41 if (b > 1u) { | |
42 if ((res = mp_sqr(&g, &g)) != MP_OKAY) { | |
43 mp_clear(&g); | |
44 return res; | |
45 } | |
46 } | |
47 | |
48 /* shift to next bit */ | |
49 b >>= 1; | |
41 } | 50 } |
51 } else { | |
52 for (x = 0; x < (unsigned)DIGIT_BIT; x++) { | |
53 /* square */ | |
54 if ((res = mp_sqr(c, c)) != MP_OKAY) { | |
55 mp_clear(&g); | |
56 return res; | |
57 } | |
42 | 58 |
43 /* square */ | 59 /* if the bit is set multiply */ |
44 if (b > 1) { | 60 if ((b & ((mp_digit)1 << (DIGIT_BIT - 1))) != 0u) { |
45 if ((res = mp_sqr (&g, &g)) != MP_OKAY) { | 61 if ((res = mp_mul(c, &g, c)) != MP_OKAY) { |
46 mp_clear (&g); | 62 mp_clear(&g); |
47 return res; | 63 return res; |
48 } | 64 } |
65 } | |
66 | |
67 /* shift to next bit */ | |
68 b <<= 1; | |
49 } | 69 } |
70 } /* if ... else */ | |
50 | 71 |
51 /* shift to next bit */ | 72 mp_clear(&g); |
52 b >>= 1; | 73 return MP_OKAY; |
53 } | |
54 } | |
55 else { | |
56 for (x = 0; x < DIGIT_BIT; x++) { | |
57 /* square */ | |
58 if ((res = mp_sqr (c, c)) != MP_OKAY) { | |
59 mp_clear (&g); | |
60 return res; | |
61 } | |
62 | |
63 /* if the bit is set multiply */ | |
64 if ((b & (mp_digit) (((mp_digit)1) << (DIGIT_BIT - 1))) != 0) { | |
65 if ((res = mp_mul (c, &g, c)) != MP_OKAY) { | |
66 mp_clear (&g); | |
67 return res; | |
68 } | |
69 } | |
70 | |
71 /* shift to next bit */ | |
72 b <<= 1; | |
73 } | |
74 } /* if ... else */ | |
75 | |
76 mp_clear (&g); | |
77 return MP_OKAY; | |
78 } | 74 } |
79 #endif | 75 #endif |
80 | 76 |
81 /* ref: $Format:%D$ */ | 77 /* ref: HEAD -> master, tag: v1.1.0 */ |
82 /* git commit: $Format:%H$ */ | 78 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ |
83 /* commit time: $Format:%ai$ */ | 79 /* commit time: 2019-01-28 20:32:32 +0100 */ |