3 * General-purpose modular exponentiation
5 * (c) 2006 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
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.
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.
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,
28 /*----- Header files ------------------------------------------------------*/
31 #include "mpbarrett.h"
34 /*----- Main code ---------------------------------------------------------*/
36 /* --- @mp_modexp@ --- *
38 * Arguments: @mp *d@ = fake destination
39 * @mp *x@ = base of exponentiation
41 * @mp *n@ = modulus (must be positive)
43 * Returns: The value %$x^e \bmod n$%.
46 mp
*mp_modexp(mp
*d
, mp
*x
, mp
*e
, mp
*n
)
50 mpmont_create(&mm
, n
);
51 d
= mpmont_exp(&mm
, d
, x
, e
);
55 mpbarrett_create(&mb
, n
);
56 d
= mpbarrett_exp(&mb
, d
, x
, e
);
57 mpbarrett_destroy(&mb
);
62 /*----- Test rig ----------------------------------------------------------*/
66 static int tmodexp(dstr
*v
)
68 mp
*a
= *(mp
**)v
[0].buf
;
69 mp
*b
= *(mp
**)v
[1].buf
;
70 mp
*m
= *(mp
**)v
[2].buf
;
71 mp
*r
= *(mp
**)v
[3].buf
;
75 mr
= mp_modexp(MP_NEW
, a
, b
, m
);
78 fputs("\n*** modexp failed", stderr
);
79 fputs("\n a = ", stderr
); mp_writefile(a
, stderr
, 10);
80 fputs("\n e = ", stderr
); mp_writefile(b
, stderr
, 10);
81 fputs("\n m = ", stderr
); mp_writefile(m
, stderr
, 10);
82 fputs("\n r = ", stderr
); mp_writefile(r
, stderr
, 10);
83 fputs("\nmr = ", stderr
); mp_writefile(mr
, stderr
, 10);
93 assert(mparena_count(MPARENA_GLOBAL
) == 0);
97 static test_chunk tests
[] = {
98 { "modexp", tmodexp
, { &type_mp
, &type_mp
, &type_mp
, &type_mp
, 0 } },
102 int main(int argc
, char *argv
[])
105 test_run(argc
, argv
, tests
, SRCDIR
"/t/mp");
111 /*----- That's all, folks -------------------------------------------------*/