Mercurial > dropbear
comparison libtommath/bn_mp_prime_next_prime.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 | a36e545fb43d |
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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_PRIME_NEXT_PRIME_C | 2 #ifdef BN_MP_PRIME_NEXT_PRIME_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 /* finds the next prime after the number "a" using "t" trials | 15 /* finds the next prime after the number "a" using "t" trials |
19 * of Miller-Rabin. | 16 * of Miller-Rabin. |
20 * | 17 * |
24 { | 21 { |
25 int err, res = MP_NO, x, y; | 22 int err, res = MP_NO, x, y; |
26 mp_digit res_tab[PRIME_SIZE], step, kstep; | 23 mp_digit res_tab[PRIME_SIZE], step, kstep; |
27 mp_int b; | 24 mp_int b; |
28 | 25 |
29 /* ensure t is valid */ | |
30 if ((t <= 0) || (t > PRIME_SIZE)) { | |
31 return MP_VAL; | |
32 } | |
33 | |
34 /* force positive */ | 26 /* force positive */ |
35 a->sign = MP_ZPOS; | 27 a->sign = MP_ZPOS; |
36 | 28 |
37 /* simple algo if a is less than the largest prime in the table */ | 29 /* simple algo if a is less than the largest prime in the table */ |
38 if (mp_cmp_d(a, ltm_prime_tab[PRIME_SIZE-1]) == MP_LT) { | 30 if (mp_cmp_d(a, ltm_prime_tab[PRIME_SIZE-1]) == MP_LT) { |
39 /* find which prime it is bigger than */ | 31 /* find which prime it is bigger than */ |
40 for (x = PRIME_SIZE - 2; x >= 0; x--) { | 32 for (x = PRIME_SIZE - 2; x >= 0; x--) { |
41 if (mp_cmp_d(a, ltm_prime_tab[x]) != MP_LT) { | 33 if (mp_cmp_d(a, ltm_prime_tab[x]) != MP_LT) { |
42 if (bbs_style == 1) { | 34 if (bbs_style == 1) { |
43 /* ok we found a prime smaller or | 35 /* ok we found a prime smaller or |
44 * equal [so the next is larger] | 36 * equal [so the next is larger] |
45 * | 37 * |
46 * however, the prime must be | 38 * however, the prime must be |
47 * congruent to 3 mod 4 | 39 * congruent to 3 mod 4 |
48 */ | 40 */ |
49 if ((ltm_prime_tab[x + 1] & 3) != 3) { | 41 if ((ltm_prime_tab[x + 1] & 3u) != 3u) { |
50 /* scan upwards for a prime congruent to 3 mod 4 */ | 42 /* scan upwards for a prime congruent to 3 mod 4 */ |
51 for (y = x + 1; y < PRIME_SIZE; y++) { | 43 for (y = x + 1; y < PRIME_SIZE; y++) { |
52 if ((ltm_prime_tab[y] & 3) == 3) { | 44 if ((ltm_prime_tab[y] & 3u) == 3u) { |
53 mp_set(a, ltm_prime_tab[y]); | 45 mp_set(a, ltm_prime_tab[y]); |
54 return MP_OKAY; | 46 return MP_OKAY; |
55 } | 47 } |
56 } | 48 } |
57 } | 49 } |
58 } else { | 50 } else { |
59 mp_set(a, ltm_prime_tab[x + 1]); | 51 mp_set(a, ltm_prime_tab[x + 1]); |
60 return MP_OKAY; | 52 return MP_OKAY; |
61 } | 53 } |
62 } | 54 } |
63 } | 55 } |
64 /* at this point a maybe 1 */ | 56 /* at this point a maybe 1 */ |
65 if (mp_cmp_d(a, 1) == MP_EQ) { | 57 if (mp_cmp_d(a, 1uL) == MP_EQ) { |
66 mp_set(a, 2); | 58 mp_set(a, 2uL); |
67 return MP_OKAY; | 59 return MP_OKAY; |
68 } | 60 } |
69 /* fall through to the sieve */ | 61 /* fall through to the sieve */ |
70 } | 62 } |
71 | 63 |
78 | 70 |
79 /* at this point we will use a combination of a sieve and Miller-Rabin */ | 71 /* at this point we will use a combination of a sieve and Miller-Rabin */ |
80 | 72 |
81 if (bbs_style == 1) { | 73 if (bbs_style == 1) { |
82 /* if a mod 4 != 3 subtract the correct value to make it so */ | 74 /* if a mod 4 != 3 subtract the correct value to make it so */ |
83 if ((a->dp[0] & 3) != 3) { | 75 if ((a->dp[0] & 3u) != 3u) { |
84 if ((err = mp_sub_d(a, (a->dp[0] & 3) + 1, a)) != MP_OKAY) { return err; }; | 76 if ((err = mp_sub_d(a, (a->dp[0] & 3u) + 1u, a)) != MP_OKAY) { |
77 return err; | |
78 }; | |
85 } | 79 } |
86 } else { | 80 } else { |
87 if (mp_iseven(a) == MP_YES) { | 81 if (mp_iseven(a) == MP_YES) { |
88 /* force odd */ | 82 /* force odd */ |
89 if ((err = mp_sub_d(a, 1, a)) != MP_OKAY) { | 83 if ((err = mp_sub_d(a, 1uL, a)) != MP_OKAY) { |
90 return err; | 84 return err; |
91 } | 85 } |
92 } | 86 } |
93 } | 87 } |
94 | 88 |
114 /* increase step to next candidate */ | 108 /* increase step to next candidate */ |
115 step += kstep; | 109 step += kstep; |
116 | 110 |
117 /* compute the new residue without using division */ | 111 /* compute the new residue without using division */ |
118 for (x = 1; x < PRIME_SIZE; x++) { | 112 for (x = 1; x < PRIME_SIZE; x++) { |
119 /* add the step to each residue */ | 113 /* add the step to each residue */ |
120 res_tab[x] += kstep; | 114 res_tab[x] += kstep; |
121 | 115 |
122 /* subtract the modulus [instead of using division] */ | 116 /* subtract the modulus [instead of using division] */ |
123 if (res_tab[x] >= ltm_prime_tab[x]) { | 117 if (res_tab[x] >= ltm_prime_tab[x]) { |
124 res_tab[x] -= ltm_prime_tab[x]; | 118 res_tab[x] -= ltm_prime_tab[x]; |
125 } | 119 } |
126 | 120 |
127 /* set flag if zero */ | 121 /* set flag if zero */ |
128 if (res_tab[x] == 0) { | 122 if (res_tab[x] == 0u) { |
129 y = 1; | 123 y = 1; |
130 } | 124 } |
131 } | 125 } |
132 } while ((y == 1) && (step < ((((mp_digit)1) << DIGIT_BIT) - kstep))); | 126 } while ((y == 1) && (step < (((mp_digit)1 << DIGIT_BIT) - kstep))); |
133 | 127 |
134 /* add the step */ | 128 /* add the step */ |
135 if ((err = mp_add_d(a, step, a)) != MP_OKAY) { | 129 if ((err = mp_add_d(a, step, a)) != MP_OKAY) { |
136 goto LBL_ERR; | 130 goto LBL_ERR; |
137 } | 131 } |
138 | 132 |
139 /* if didn't pass sieve and step == MAX then skip test */ | 133 /* if didn't pass sieve and step == MAX then skip test */ |
140 if ((y == 1) && (step >= ((((mp_digit)1) << DIGIT_BIT) - kstep))) { | 134 if ((y == 1) && (step >= (((mp_digit)1 << DIGIT_BIT) - kstep))) { |
141 continue; | 135 continue; |
142 } | 136 } |
143 | 137 |
144 /* is this prime? */ | 138 if ((err = mp_prime_is_prime(a, t, &res)) != MP_OKAY) { |
145 for (x = 0; x < t; x++) { | 139 goto LBL_ERR; |
146 mp_set(&b, ltm_prime_tab[x]); | |
147 if ((err = mp_prime_miller_rabin(a, &b, &res)) != MP_OKAY) { | |
148 goto LBL_ERR; | |
149 } | |
150 if (res == MP_NO) { | |
151 break; | |
152 } | |
153 } | 140 } |
154 | |
155 if (res == MP_YES) { | 141 if (res == MP_YES) { |
156 break; | 142 break; |
157 } | 143 } |
158 } | 144 } |
159 | 145 |
163 return err; | 149 return err; |
164 } | 150 } |
165 | 151 |
166 #endif | 152 #endif |
167 | 153 |
168 /* ref: $Format:%D$ */ | 154 /* ref: HEAD -> master, tag: v1.1.0 */ |
169 /* git commit: $Format:%H$ */ | 155 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ |
170 /* commit time: $Format:%ai$ */ | 156 /* commit time: 2019-01-28 20:32:32 +0100 */ |