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/*
* exptmod.c
*
* Command line tool to perform modular exponentiation on arbitrary
* precision integers.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mpi.h"
int
main(int argc, char *argv[])
{
mp_int a, b, m;
mp_err res;
char *str;
int len, rval = 0;
if (argc < 3) {
fprintf(stderr, "Usage: %s <a> <b> <m>\n", argv[0]);
return 1;
}
mp_init(&a);
mp_init(&b);
mp_init(&m);
mp_read_radix(&a, argv[1], 10);
mp_read_radix(&b, argv[2], 10);
mp_read_radix(&m, argv[3], 10);
if ((res = mp_exptmod(&a, &b, &m, &a)) != MP_OKAY) {
fprintf(stderr, "%s: error: %s\n", argv[0], mp_strerror(res));
rval = 1;
} else {
len = mp_radix_size(&a, 10);
str = calloc(len, sizeof(char));
mp_toradix(&a, str, 10);
printf("%s\n", str);
free(str);
}
mp_clear(&a);
mp_clear(&b);
mp_clear(&m);
return rval;
}
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