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comparison libtommath/bn_mp_reduce_is_2k.c @ 1655:f52919ffd3b1

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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_IS_2K_C 2 #ifdef BN_MP_REDUCE_IS_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 /* determines if mp_reduce_2k can be used */ 15 /* determines if mp_reduce_2k can be used */
19 int mp_reduce_is_2k(mp_int *a) 16 int mp_reduce_is_2k(const mp_int *a)
20 { 17 {
21 int ix, iy, iw; 18 int ix, iy, iw;
22 mp_digit iz; 19 mp_digit iz;
23 20
24 if (a->used == 0) { 21 if (a->used == 0) {
25 return MP_NO; 22 return MP_NO;
26 } else if (a->used == 1) { 23 } else if (a->used == 1) {
27 return MP_YES; 24 return MP_YES;
28 } else if (a->used > 1) { 25 } else if (a->used > 1) {
29 iy = mp_count_bits(a); 26 iy = mp_count_bits(a);
30 iz = 1; 27 iz = 1;
31 iw = 1; 28 iw = 1;
32 29
33 /* Test every bit from the second digit up, must be 1 */ 30 /* Test every bit from the second digit up, must be 1 */
34 for (ix = DIGIT_BIT; ix < iy; ix++) { 31 for (ix = DIGIT_BIT; ix < iy; ix++) {
35 if ((a->dp[iw] & iz) == 0) { 32 if ((a->dp[iw] & iz) == 0u) {
36 return MP_NO; 33 return MP_NO;
37 } 34 }
38 iz <<= 1; 35 iz <<= 1;
39 if (iz > (mp_digit)MP_MASK) { 36 if (iz > (mp_digit)MP_MASK) {
40 ++iw; 37 ++iw;
41 iz = 1; 38 iz = 1;
42 } 39 }
43 } 40 }
44 } 41 }
45 return MP_YES; 42 return MP_YES;
46 } 43 }
47 44
48 #endif 45 #endif
49 46
50 /* ref: $Format:%D$ */ 47 /* ref: HEAD -> master, tag: v1.1.0 */
51 /* git commit: $Format:%H$ */ 48 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
52 /* commit time: $Format:%ai$ */ 49 /* commit time: 2019-01-28 20:32:32 +0100 */