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/* prime.c - part of the Libgcrypt test suite.
Copyright (C) 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define PGM "prime"
#include "t-common.h"
static void
check_primes (void)
{
gcry_error_t err = GPG_ERR_NO_ERROR;
gcry_mpi_t *factors = NULL;
gcry_mpi_t prime = NULL;
gcry_mpi_t g;
unsigned int i = 0;
struct prime_spec
{
unsigned int prime_bits;
unsigned int factor_bits;
unsigned int flags;
} prime_specs[] =
{
{ 1024, 100, GCRY_PRIME_FLAG_SPECIAL_FACTOR },
{ 128, 0, 0 },
{ 0 },
};
for (i = 0; prime_specs[i].prime_bits; i++)
{
err = gcry_prime_generate (&prime,
prime_specs[i].prime_bits,
prime_specs[i].factor_bits,
&factors,
NULL, NULL,
GCRY_WEAK_RANDOM,
prime_specs[i].flags);
assert (! err);
if (verbose)
{
fprintf (stderr, "test %d: p = ", i);
gcry_mpi_dump (prime);
putc ('\n', stderr);
}
err = gcry_prime_check (prime, 0);
assert (! err);
err = gcry_prime_group_generator (&g, prime, factors, NULL);
assert (!err);
gcry_prime_release_factors (factors); factors = NULL;
if (verbose)
{
fprintf (stderr, " %d: g = ", i);
gcry_mpi_dump (g);
putc ('\n', stderr);
}
gcry_mpi_release (g);
gcry_mpi_add_ui (prime, prime, 1);
err = gcry_prime_check (prime, 0);
assert (err);
gcry_mpi_release (prime); prime = NULL;
}
}
/* Print an MPI S-expression. */
static void
print_mpi (const char *name, gcry_mpi_t a)
{
gcry_error_t err;
unsigned char *buf;
int writerr = 0;
err = gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buf, NULL, a);
if (err)
die ("gcry_mpi_aprint failed: %s\n", gcry_strerror (err));
printf (" (%s #%s#)\n", name, buf);
if (ferror (stdout))
writerr++;
if (!writerr && fflush (stdout) == EOF)
writerr++;
if (writerr)
die ("writing output failed\n");
gcry_free (buf);
}
/* Create the key for our public standard dummy CA. */
static void
create_42prime (void)
{
gcry_error_t err;
char string[128*2+1];
int i;
gcry_mpi_t start = NULL;
gcry_mpi_t p, q, n, t1, t2, phi, f, g, e, d, u;
/* Our start value is a string of 0x42 values, with the exception
that the two high order bits are set. This is to resemble the
way Lingcrypt generates RSA primes. */
for (i=0; i < 128;)
{
string[i++] = '4';
string[i++] = '2';
}
string[i] = 0;
string[0] = 'C';
err = gcry_mpi_scan (&start, GCRYMPI_FMT_HEX, string, 0, NULL);
if (err)
die ("gcry_mpi_scan failed: %s\n", gcry_strerror (err));
fputs ("start:", stderr); gcry_mpi_dump (start); putc ('\n', stderr);
/* Generate two primes with p < q. We take the first primes below
and above a start value. */
p = gcry_mpi_copy (start);
gcry_mpi_sub_ui (p, p, 1);
while (gcry_prime_check (p, 0))
gcry_mpi_sub_ui (p, p, 2);
fputs (" p:", stderr); gcry_mpi_dump (p); putc ('\n', stderr);
q = gcry_mpi_copy (start);
gcry_mpi_add_ui (q, q, 1);
while (gcry_prime_check (q, 0))
gcry_mpi_add_ui (q, q, 2);
fputs (" q:", stderr); gcry_mpi_dump (q); putc ('\n', stderr);
/* Compute the modulus. */
n = gcry_mpi_new (1024);
gcry_mpi_mul (n, p, q);
fputs (" n:", stderr); gcry_mpi_dump (n); putc ('\n', stderr);
if (gcry_mpi_get_nbits (n) != 1024)
die ("Oops: the size of N is not 1024 but %u\n", gcry_mpi_get_nbits (n));
/* Calculate Euler totient: phi = (p-1)(q-1) */
t1 = gcry_mpi_new (0);
t2 = gcry_mpi_new (0);
phi = gcry_mpi_new (0);
g = gcry_mpi_new (0);
f = gcry_mpi_new (0);
gcry_mpi_sub_ui (t1, p, 1);
gcry_mpi_sub_ui (t2, q, 1);
gcry_mpi_mul (phi, t1, t2);
gcry_mpi_gcd (g, t1, t2);
gcry_mpi_div (f, NULL, phi, g, -1);
/* Check the public exponent. */
e = gcry_mpi_set_ui (NULL, 65537);
if (!gcry_mpi_gcd (t1, e, phi))
die ("Oops: E is not a generator\n");
fputs (" e:", stderr); gcry_mpi_dump (e); putc ('\n', stderr);
/* Compute the secret key: d = e^-1 mod phi */
d = gcry_mpi_new (0);
gcry_mpi_invm (d, e, f );
fputs (" d:", stderr); gcry_mpi_dump (d); putc ('\n', stderr);
/* Compute the inverse of p and q. */
u = gcry_mpi_new (0);
gcry_mpi_invm (u, p, q);
fputs (" u:", stderr); gcry_mpi_dump (u); putc ('\n', stderr);
/* Print the S-expression. */
fputs ("(private-key\n (rsa\n", stdout);
print_mpi ("n", n);
print_mpi ("e", e);
print_mpi ("d", d);
print_mpi ("p", p);
print_mpi ("q", q);
print_mpi ("u", u);
fputs ("))\n", stdout);
gcry_mpi_release (p);
gcry_mpi_release (q);
gcry_mpi_release (n);
gcry_mpi_release (t1);
gcry_mpi_release (t2);
gcry_mpi_release (phi);
gcry_mpi_release (f);
gcry_mpi_release (g);
gcry_mpi_release (e);
gcry_mpi_release (d);
gcry_mpi_release (u);
}
int
main (int argc, char **argv)
{
int mode42 = 0;
if ((argc > 1) && (! strcmp (argv[1], "--verbose")))
verbose = 1;
else if ((argc > 1) && (! strcmp (argv[1], "--debug")))
verbose = debug = 1;
else if ((argc > 1) && (! strcmp (argv[1], "--42")))
verbose = debug = mode42 = 1;
xgcry_control ((GCRYCTL_DISABLE_SECMEM, 0));
if (! gcry_check_version (GCRYPT_VERSION))
die ("version mismatch\n");
xgcry_control ((GCRYCTL_INITIALIZATION_FINISHED, 0));
if (debug)
xgcry_control ((GCRYCTL_SET_DEBUG_FLAGS, 1u, 0));
if (mode42)
create_42prime ();
else
check_primes ();
return 0;
}

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