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1 | /* -*-c-*- |
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2 | * |
3 | * Multiple simultaneous exponentiations |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include "mp.h" |
31 | #include "mpbarrett.h" |
32 | |
33 | #define EXP_WINSZ 3 |
34 | #include "mpbarrett-exp.h" |
35 | |
36 | /*----- Main code ---------------------------------------------------------*/ |
37 | |
38 | /* --- @mpbarrett_mexp@ --- * |
39 | * |
40 | * Arguments: @mpbarrett *mb@ = pointer to Barrett reduction context |
41 | * @mp *d@ = fake destination |
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42 | * @const mp_expfactor *f@ = pointer to array of factors |
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43 | * @size_t n@ = number of factors supplied |
44 | * |
45 | * Returns: If the bases are %$g_0, g_1, \ldots, g_{n-1}$% and the |
46 | * exponents are %$e_0, e_1, \ldots, e_{n-1}$% then the result |
47 | * is: |
48 | * |
49 | * %$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$% |
50 | */ |
51 | |
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52 | mp *mpbarrett_mexp(mpbarrett *mb, mp *d, const mp_expfactor *f, size_t n) |
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53 | { |
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54 | mp_expfactor *ff = xmalloc(n * sizeof(mp_expfactor)); |
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55 | mp *a = MP_ONE; |
56 | mp *spare; |
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57 | mp *g = MP_NEW; |
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58 | size_t i; |
59 | |
60 | spare = MP_NEW; |
61 | for (i = 0; i < n; i++) { |
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62 | if (f[i].exp->f & MP_BURN) |
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63 | spare = MP_NEWSEC; |
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64 | if (MP_NEGP(f[i].exp)) |
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65 | ff[i].base = mp_modinv(MP_NEW, f[i].base, mb->m); |
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66 | else |
67 | ff[i].base = MP_COPY(f[i].base); |
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68 | ff[i].exp = f[i].exp; |
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69 | } |
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70 | mp_drop(g); |
71 | EXP_SIMUL(a, ff, n); |
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72 | mp_drop(d); |
73 | mp_drop(spare); |
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74 | for (i = 0; i < n; i++) |
75 | mp_drop(ff[i].base); |
76 | xfree(ff); |
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77 | return (a); |
78 | } |
79 | |
80 | /*----- Test rig ----------------------------------------------------------*/ |
81 | |
82 | #ifdef TEST_RIG |
83 | |
84 | #include <mLib/testrig.h> |
85 | |
86 | static int verify(size_t n, dstr *v) |
87 | { |
88 | mp *m = *(mp **)v[0].buf; |
89 | mp_expfactor *f = xmalloc(n * sizeof(*f)); |
90 | mp *r, *rr; |
91 | size_t i, j; |
92 | mpbarrett mb; |
93 | int ok = 1; |
94 | |
95 | j = 1; |
96 | for (i = 0; i < n; i++) { |
97 | f[i].base = *(mp **)v[j++].buf; |
98 | f[i].exp = *(mp **)v[j++].buf; |
99 | } |
100 | |
101 | rr = *(mp **)v[j].buf; |
102 | mpbarrett_create(&mb, m); |
103 | r = mpbarrett_mexp(&mb, MP_NEW, f, n); |
104 | if (!MP_EQ(r, rr)) { |
105 | fputs("\n*** mexp failed\n", stderr); |
106 | fputs("m = ", stderr); mp_writefile(m, stderr, 10); |
107 | for (i = 0; i < n; i++) { |
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108 | fprintf(stderr, "\ng_%lu = ", (unsigned long)i); |
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109 | mp_writefile(f[i].base, stderr, 10); |
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110 | fprintf(stderr, "\ne_%lu = ", (unsigned long)i); |
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111 | mp_writefile(f[i].exp, stderr, 10); |
112 | } |
113 | fputs("\nr = ", stderr); mp_writefile(r, stderr, 10); |
114 | fputs("\nR = ", stderr); mp_writefile(rr, stderr, 10); |
115 | fputc('\n', stderr); |
116 | ok = 0; |
117 | } |
118 | |
119 | for (i = 0; i < n; i++) { |
120 | MP_DROP(f[i].base); |
121 | MP_DROP(f[i].exp); |
122 | } |
123 | MP_DROP(m); |
124 | MP_DROP(r); |
125 | MP_DROP(rr); |
126 | mpbarrett_destroy(&mb); |
127 | assert(mparena_count(MPARENA_GLOBAL) == 0); |
128 | return (ok); |
129 | } |
130 | |
131 | static int t1(dstr *v) { return verify(1, v); } |
132 | static int t2(dstr *v) { return verify(2, v); } |
133 | static int t3(dstr *v) { return verify(3, v); } |
134 | static int t4(dstr *v) { return verify(4, v); } |
135 | static int t5(dstr *v) { return verify(5, v); } |
136 | |
137 | static test_chunk tests[] = { |
138 | { "mexp-1", t1, { &type_mp, |
139 | &type_mp, &type_mp, |
140 | &type_mp, 0 } }, |
141 | { "mexp-2", t2, { &type_mp, |
142 | &type_mp, &type_mp, |
143 | &type_mp, &type_mp, |
144 | &type_mp, 0 } }, |
145 | { "mexp-3", t3, { &type_mp, |
146 | &type_mp, &type_mp, |
147 | &type_mp, &type_mp, |
148 | &type_mp, &type_mp, |
149 | &type_mp, 0 } }, |
150 | { "mexp-4", t4, { &type_mp, |
151 | &type_mp, &type_mp, |
152 | &type_mp, &type_mp, |
153 | &type_mp, &type_mp, |
154 | &type_mp, &type_mp, |
155 | &type_mp, 0 } }, |
156 | { "mexp-5", t5, { &type_mp, |
157 | &type_mp, &type_mp, |
158 | &type_mp, &type_mp, |
159 | &type_mp, &type_mp, |
160 | &type_mp, &type_mp, |
161 | &type_mp, &type_mp, |
162 | &type_mp, 0 } }, |
163 | { 0, 0, { 0 } } |
164 | }; |
165 | |
166 | int main(int argc, char *argv[]) |
167 | { |
168 | sub_init(); |
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169 | test_run(argc, argv, tests, SRCDIR "/t/mpbarrett"); |
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170 | return (0); |
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171 | } |
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172 | |
173 | #endif |
174 | |
175 | /*----- That's all, folks -------------------------------------------------*/ |