3 * $Id: mpmont-mexp.c,v 1.8 2004/04/01 12:50:09 mdw Exp $
5 * Multiple simultaneous exponentiations
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Revision history --------------------------------------------------*
32 * $Log: mpmont-mexp.c,v $
33 * Revision 1.8 2004/04/01 12:50:09 mdw
34 * Add cyclic group abstraction, with test code. Separate off exponentation
35 * functions for better static linking. Fix a buttload of bugs on the way.
36 * Generally ensure that negative exponents do inversion correctly. Add
37 * table of standard prime-field subgroups. (Binary field subgroups are
38 * currently unimplemented but easy to add if anyone ever finds a good one.)
40 * Revision 1.7 2002/01/13 13:49:14 mdw
41 * Make @const@-correct.
43 * Revision 1.6 2001/06/16 13:00:20 mdw
44 * Use the generic exponentiation functions.
46 * Revision 1.5 2000/10/08 12:11:22 mdw
47 * Use @MP_EQ@ instead of @MP_CMP@.
49 * Revision 1.4 2000/06/17 11:45:09 mdw
50 * Major memory management overhaul. Added arena support. Use the secure
51 * arena for secret integers. Replace and improve the MP management macros
52 * (e.g., replace MP_MODIFY by MP_DEST).
54 * Revision 1.3 1999/12/10 23:18:39 mdw
55 * Change interface for suggested destinations.
57 * Revision 1.2 1999/11/21 11:35:10 mdw
58 * Performance improvement: use @mp_sqr@ and @mpmont_reduce@ instead of
59 * @mpmont_mul@ for squaring in exponentiation.
61 * Revision 1.1 1999/11/19 13:19:29 mdw
62 * Simultaneous exponentiation support.
66 /*----- Header files ------------------------------------------------------*/
72 #include "mpmont-exp.h"
74 /*----- Main code ---------------------------------------------------------*/
76 /* --- @mpmont_mexpr@ --- *
78 * Arguments: @mpmont *mm@ = pointer to Montgomery reduction context
79 * @mp *d@ = fake destination
80 * @const mp_expfactor *f@ = pointer to array of factors
81 * @size_t n@ = number of factors supplied
83 * Returns: If the bases are %$g_0, g_1, \ldots, g_{n-1}$% and the
84 * exponents are %$e_0, e_1, \ldots, e_{n-1}$% then the result
87 * %$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$%
89 * except that the %$g_i$% and result are in Montgomery form.
92 static mp
*mexpr(mpmont
*mm
, mp
*d
, mp_expfactor
*f
, size_t n
)
94 mp
*a
= MP_COPY(mm
->r
);
99 for (i
= 0; i
< n
; i
++) {
101 if (f
[i
].exp
->f
& MP_BURN
)
103 if (f
[i
].exp
->f
& MP_NEG
) {
104 t
= mpmont_reduce(mm
, f
[i
].base
, f
[i
].base
);
105 mp_gcd(&g
, 0, &t
, mm
->m
, t
);
106 assert(MP_EQ(g
, MP_ONE
));
107 f
[i
].base
= mpmont_mul(mm
, t
, t
, mm
->r2
);
114 for (i
= 0; i
< n
; i
++)
120 mp
*mpmont_mexpr(mpmont
*mm
, mp
*d
, const mp_expfactor
*f
, size_t n
)
122 mp_expfactor
*ff
= xmalloc(n
* sizeof(mp_expfactor
));
125 for (i
= 0; i
< n
; i
++) {
126 ff
[i
].base
= MP_COPY(f
[i
].base
);
127 ff
[i
].exp
= f
[i
].exp
;
129 return (mexpr(mm
, d
, ff
, n
));
132 /* --- @mpmont_mexp@ --- *
134 * Arguments: @mpmont *mm@ = pointer to Montgomery reduction context
135 * @mp *d@ = fake destination
136 * @const mp_expfactor *f@ = pointer to array of factors
137 * @size_t n@ = number of factors supplied
139 * Returns: Product of bases raised to exponents, all mod @m@.
141 * Use: Convenient interface over @mpmont_mexpr@.
144 mp
*mpmont_mexp(mpmont
*mm
, mp
*d
, const mp_expfactor
*f
, size_t n
)
146 mp_expfactor
*ff
= xmalloc(n
* sizeof(mp_expfactor
));
149 for (i
= 0; i
< n
; i
++) {
150 ff
[i
].base
= mpmont_mul(mm
, MP_NEW
, f
[i
].base
, mm
->r2
);
151 ff
[i
].exp
= f
[i
].exp
;
153 d
= mexpr(mm
, d
, ff
, n
);
154 return (mpmont_reduce(mm
, d
, d
));
157 /*----- Test rig ----------------------------------------------------------*/
161 #include <mLib/testrig.h>
163 static int verify(size_t n
, dstr
*v
)
165 mp
*m
= *(mp
**)v
[0].buf
;
166 mp_expfactor
*f
= xmalloc(n
* sizeof(*f
));
173 for (i
= 0; i
< n
; i
++) {
174 f
[i
].base
= *(mp
**)v
[j
++].buf
;
175 f
[i
].exp
= *(mp
**)v
[j
++].buf
;
178 rr
= *(mp
**)v
[j
].buf
;
179 mpmont_create(&mm
, m
);
180 r
= mpmont_mexp(&mm
, MP_NEW
, f
, n
);
182 fputs("\n*** mexp failed\n", stderr
);
183 fputs("m = ", stderr
); mp_writefile(m
, stderr
, 10);
184 for (i
= 0; i
< n
; i
++) {
185 fprintf(stderr
, "\ng_%u = ", i
);
186 mp_writefile(f
[i
].base
, stderr
, 10);
187 fprintf(stderr
, "\ne_%u = ", i
);
188 mp_writefile(f
[i
].exp
, stderr
, 10);
190 fputs("\nr = ", stderr
); mp_writefile(r
, stderr
, 10);
191 fputs("\nR = ", stderr
); mp_writefile(rr
, stderr
, 10);
196 for (i
= 0; i
< n
; i
++) {
204 assert(mparena_count(MPARENA_GLOBAL
) == 0);
208 static int t1(dstr
*v
) { return verify(1, v
); }
209 static int t2(dstr
*v
) { return verify(2, v
); }
210 static int t3(dstr
*v
) { return verify(3, v
); }
211 static int t4(dstr
*v
) { return verify(4, v
); }
212 static int t5(dstr
*v
) { return verify(5, v
); }
214 static test_chunk tests
[] = {
215 { "mexp-1", t1
, { &type_mp
,
218 { "mexp-2", t2
, { &type_mp
,
222 { "mexp-3", t3
, { &type_mp
,
227 { "mexp-4", t4
, { &type_mp
,
233 { "mexp-5", t5
, { &type_mp
,
243 int main(int argc
, char *argv
[])
246 test_run(argc
, argv
, tests
, SRCDIR
"/tests/mpmont");
252 /*----- That's all, folks -------------------------------------------------*/