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@kazkansouh
Created December 13, 2019 17:57
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Command line app to call openssl primality check
/* Copyright (C) 2019 Karim Kanso. All Rights Reserved.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* Trivial program to call the openssl primality check from the
* command line.
*
* Usage, pass prime number to test as first parameter on command
* line.
*
* Exit code:
* 2 - Error
* 1 - Is Prime
* 0 - Not Prime
*
* Compile:
* gcc -Wall -Wpedantic -c prime-test.c -o prime-test.o
* gcc prime-test.o -lcrypto -o prime-test
*/
#include <stdio.h>
#include <string.h>
#include <openssl/bn.h>
int main(int argc, char** argv) {
if (argc != 2) {
fputs("usage: provide the prime number as sole argument\n", stderr);
return 1;
}
int i_ret = 2;
BIGNUM *p_bn = BN_new();
BN_CTX *p_bn_ctx = BN_CTX_new();
if (BN_dec2bn(&p_bn, argv[1]) != strlen(argv[1])) {
fputs("bad integer\n", stderr);
goto cleanup;
}
int i_bits = BN_num_bits(p_bn);
switch (BN_is_prime_ex(p_bn, i_bits / 2, p_bn_ctx, NULL)) {
case -1:
fputs("prime check failed\n", stderr);
break;
case 1:
fputs("is prime\n", stdout);
i_ret = 0;
break;
case 0:
fputs("not prime\n", stdout);
i_ret = 1;
break;
default:
fputs("internal error\n", stderr);
break;
}
cleanup:
BN_free(p_bn);
p_bn = NULL;
BN_CTX_free(p_bn_ctx);
p_bn_ctx = NULL;
return i_ret;
}
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