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1 /* | 1 /* |
2 * Blum, Blum & Shub PRNG using the MPI library | 2 * Blum, Blum & Shub PRNG using the MPI library |
3 * | 3 * |
4 * This Source Code Form is subject to the terms of the Mozilla Public | 4 * This Source Code Form is subject to the terms of the Mozilla Public |
5 * License, v. 2.0. If a copy of the MPL was not distributed with this | 5 * License, v. 2.0. If a copy of the MPL was not distributed with this |
6 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | 6 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
7 | 7 |
8 #include "bbs_rand.h" | 8 #include "bbs_rand.h" |
9 | 9 |
10 #define SEED 1 | 10 #define SEED 1 |
11 #define MODULUS 2 | 11 #define MODULUS 2 |
12 | 12 |
13 /* This modulus is the product of two randomly generated 512-bit | 13 /* This modulus is the product of two randomly generated 512-bit |
14 prime integers, each of which is congruent to 3 (mod 4). */ | 14 prime integers, each of which is congruent to 3 (mod 4). */ |
15 static char *bbs_modulus =· | 15 static char *bbs_modulus = |
16 "75A2A6E1D27393B86562B9CE7279A8403CB4258A637DAB5233465373E37837383EDC" | 16 "75A2A6E1D27393B86562B9CE7279A8403CB4258A637DAB5233465373E37837383EDC" |
17 "332282B8575927BC4172CE8C147B4894050EE9D2BDEED355C121037270CA2570D127" | 17 "332282B8575927BC4172CE8C147B4894050EE9D2BDEED355C121037270CA2570D127" |
18 "7D2390CD1002263326635CC6B259148DE3A1A03201980A925E395E646A5E9164B0EC" | 18 "7D2390CD1002263326635CC6B259148DE3A1A03201980A925E395E646A5E9164B0EC" |
19 "28559EBA58C87447245ADD0651EDA507056A1129E3A3E16E903D64B437"; | 19 "28559EBA58C87447245ADD0651EDA507056A1129E3A3E16E903D64B437"; |
20 | 20 |
21 static int bbs_init = 0; /* flag set when library is initialized */ | 21 static int bbs_init = 0; /* flag set when library is initialized */ |
22 static mp_int bbs_state; /* the current state of the generator */ | 22 static mp_int bbs_state; /* the current state of the generator */ |
23 | 23 |
24 /* Suggested size of random seed data */ | 24 /* Suggested size of random seed data */ |
25 int bbs_seed_size = (sizeof(bbs_modulus) / 2); | 25 int bbs_seed_size = (sizeof(bbs_modulus) / 2); |
26 | 26 |
27 void bbs_srand(unsigned char *data, int len) | 27 void bbs_srand(unsigned char *data, int len) { |
28 { | 28 if ((bbs_init & SEED) == 0) { |
29 if((bbs_init & SEED) == 0) { | |
30 mp_init(&bbs_state); | 29 mp_init(&bbs_state); |
31 bbs_init |= SEED; | 30 bbs_init |= SEED; |
32 } | 31 } |
33 | 32 |
34 mp_read_raw(&bbs_state, (char *)data, len); | 33 mp_read_raw(&bbs_state, (char *)data, len); |
35 | 34 |
36 } /* end bbs_srand() */ | 35 } /* end bbs_srand() */ |
37 | 36 |
38 unsigned int bbs_rand(void) | 37 unsigned int bbs_rand(void) { |
39 { | 38 static mp_int modulus; |
40 static mp_int modulus; | 39 unsigned int result = 0, ix; |
41 unsigned int result = 0, ix; | |
42 | 40 |
43 if((bbs_init & MODULUS) == 0) { | 41 if ((bbs_init & MODULUS) == 0) { |
44 mp_init(&modulus); | 42 mp_init(&modulus); |
45 mp_read_radix(&modulus, bbs_modulus, 16); | 43 mp_read_radix(&modulus, bbs_modulus, 16); |
46 bbs_init |= MODULUS; | 44 bbs_init |= MODULUS; |
47 } | 45 } |
48 | 46 |
49 for(ix = 0; ix < sizeof(unsigned int); ix++) { | 47 for (ix = 0; ix < sizeof(unsigned int); ix++) { |
50 mp_digit d; | 48 mp_digit d; |
51 | 49 |
52 mp_sqrmod(&bbs_state, &modulus, &bbs_state); | 50 mp_sqrmod(&bbs_state, &modulus, &bbs_state); |
53 d = DIGIT(&bbs_state, 0); | 51 d = DIGIT(&bbs_state, 0); |
54 | 52 |
55 result = (result << CHAR_BIT) | (d & UCHAR_MAX); | 53 result = (result << CHAR_BIT) | (d & UCHAR_MAX); |
56 } | 54 } |
57 | 55 |
58 return result; | 56 return result; |
59 | 57 |
60 } /* end bbs_rand() */ | 58 } /* end bbs_rand() */ |
61 | 59 |
62 /*------------------------------------------------------------------------*/ | 60 /*------------------------------------------------------------------------*/ |
63 /* HERE THERE BE DRAGONS */ | 61 /* HERE THERE BE DRAGONS */ |
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