/* primegen.c - prime number generator
* Copyright (C) 1998, 2000, 2001, 2002, 2003
- * 2004 Free Software Foundation, Inc.
+ * 2004, 2008 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
-#include <assert.h>
#include <errno.h>
#include "g10lib.h"
#include "cipher.h"
#include "ath.h"
-static gcry_mpi_t gen_prime (unsigned int nbits, int secret, int randomlevel,
+static gcry_mpi_t gen_prime (unsigned int nbits, int secret, int randomlevel,
int (*extra_check)(void *, gcry_mpi_t),
void *extra_check_arg);
static int check_prime( gcry_mpi_t prime, gcry_mpi_t val_2, int rm_rounds,
\f
/* An object and a list to build up a global pool of primes. See
save_pool_prime and get_pool_prime. */
-struct primepool_s
+struct primepool_s
{
struct primepool_s *next;
gcry_mpi_t prime; /* If this is NULL the entry is not used. */
};
struct primepool_s *primepool;
/* Mutex used to protect access to the primepool. */
-static ath_mutex_t primepool_lock = ATH_MUTEX_INITIALIZER;
+static ath_mutex_t primepool_lock;
+gcry_err_code_t
+_gcry_primegen_init (void)
+{
+ gcry_err_code_t ec;
+
+ ec = ath_mutex_init (&primepool_lock);
+ if (ec)
+ return gpg_err_code_from_errno (ec);
+ return ec;
+}
+
/* Save PRIME which has been generated at RANDOMLEVEL for later
use. Needs to be called while primepool_lock is being hold. Note
/* Remove some of the entries. Our strategy is removing
the last third from the list. */
int i;
-
+
for (i=0, item2 = primepool; item2; item2 = item2->next)
{
if (i >= n/3*2)
{
- gcry_mpi_release (item2->prime);
+ _gcry_mpi_release (item2->prime);
item2->prime = NULL;
if (!item)
item = item2;
}
if (!item)
{
- item = gcry_calloc (1, sizeof *item);
+ item = xtrycalloc (1, sizeof *item);
if (!item)
{
/* Out of memory. Silently giving up. */
- gcry_mpi_release (prime);
- return;
+ _gcry_mpi_release (prime);
+ return;
}
item->next = primepool;
primepool = item;
/* Return a prime for the prime pool or NULL if none has been found.
The prime needs to match NBITS and randomlevel. This function needs
- to be called why the primepool_look is being hold. */
+ to be called with the primepool_look is being hold. */
static gcry_mpi_t
get_pool_prime (unsigned int nbits, gcry_random_level_t randomlevel)
{
{
gcry_mpi_t prime = item->prime;
item->prime = NULL;
- assert (nbits == mpi_get_nbits (prime));
+ gcry_assert (nbits == mpi_get_nbits (prime));
return prime;
}
return NULL;
*/
gcry_mpi_t
_gcry_generate_secret_prime (unsigned int nbits,
+ gcry_random_level_t random_level,
int (*extra_check)(void*, gcry_mpi_t),
void *extra_check_arg)
{
gcry_mpi_t prime;
- prime = gen_prime( nbits, 1, 2, extra_check, extra_check_arg);
+ prime = gen_prime (nbits, 1, random_level, extra_check, extra_check_arg);
progress('\n');
return prime;
}
+
+/* Generate a prime number which may be public, i.e. not allocated in
+ secure memory. */
gcry_mpi_t
-_gcry_generate_public_prime( unsigned int nbits,
+_gcry_generate_public_prime (unsigned int nbits,
+ gcry_random_level_t random_level,
int (*extra_check)(void*, gcry_mpi_t),
void *extra_check_arg)
{
gcry_mpi_t prime;
- prime = gen_prime( nbits, 0, 2, extra_check, extra_check_arg );
+ prime = gen_prime (nbits, 0, random_level, extra_check, extra_check_arg);
progress('\n');
return prime;
}
fbits = (pbits - req_qbits -1) / n;
qbits = pbits - n * fbits;
}
-
+
if (DBG_CIPHER)
log_debug ("gen prime: pbits=%u qbits=%u fbits=%u/%u n=%d\n",
pbits, req_qbits, qbits, fbits, n);
/* Allocate an integer to old the new prime. */
- prime = gcry_mpi_new (pbits);
+ prime = mpi_new (pbits);
/* Generate first prime factor. */
q = gen_prime (qbits, is_secret, randomlevel, NULL, NULL);
/* Generate a specific Q-Factor if requested. */
if (need_q_factor)
q_factor = gen_prime (req_qbits, is_secret, randomlevel, NULL, NULL);
-
+
/* Allocate an array to hold all factors + 2 for later usage. */
- factors = gcry_calloc (n + 2, sizeof (*factors));
+ factors = xtrycalloc (n + 2, sizeof (*factors));
if (!factors)
{
err = gpg_err_code_from_errno (errno);
}
/* Allocate an array to track pool usage. */
- pool_in_use = gcry_malloc (n * sizeof *pool_in_use);
+ pool_in_use = xtrymalloc (n * sizeof *pool_in_use);
if (!pool_in_use)
{
err = gpg_err_code_from_errno (errno);
}
for (i=0; i < n; i++)
pool_in_use[i] = -1;
-
+
/* Make a pool of 3n+5 primes (this is an arbitrary value). We
- require at least 30 primes for are useful selection process.
-
- FIXME: We need to do some reseacrh on the best formula for sizing
- the pool.
+ require at least 30 primes for are useful selection process.
+
+ Fixme: We need to research the best formula for sizing the pool.
*/
m = n * 3 + 5;
if (need_q_factor) /* Need some more in this case. */
m += 5;
if (m < 30)
m = 30;
- pool = gcry_calloc (m , sizeof (*pool));
+ pool = xtrycalloc (m , sizeof (*pool));
if (! pool)
{
err = gpg_err_code_from_errno (errno);
}
/* Init m_out_of_n(). */
- perms = gcry_calloc (1, m);
+ perms = xtrycalloc (1, m);
if (!perms)
{
err = gpg_err_code_from_errno (errno);
is_locked = 1;
for (i = 0; i < n; i++)
{
- perms[i] = 1;
+ perms[i] = 1;
/* At a maximum we use strong random for the factors.
This saves us a lot of entropy. Given that Q and
possible Q-factor are also used in the final prime
if (i == n)
{
/* Ran out of permutations: Allocate new primes. */
- gcry_free (perms);
+ xfree (perms);
perms = NULL;
progress ('!');
- goto next_try;
+ goto next_try;
}
}
/* Generate next prime candidate:
- p = 2 * q [ * q_factor] * factor_0 * factor_1 * ... * factor_n + 1.
+ p = 2 * q [ * q_factor] * factor_0 * factor_1 * ... * factor_n + 1.
*/
mpi_set (prime, q);
mpi_mul_ui (prime, prime, 2);
}
else
count1 = 0;
-
+
if (nprime > pbits)
{
if (++count2 > 20)
if (DBG_CIPHER)
{
progress ('\n');
- log_mpidump ("prime : ", prime);
- log_mpidump ("factor q: ", q);
+ log_mpidump ("prime ", prime);
+ log_mpidump ("factor q", q);
if (need_q_factor)
- log_mpidump ("factor q0: ", q_factor);
+ log_mpidump ("factor q0", q_factor);
for (i = 0; i < n; i++)
- log_mpidump ("factor pi: ", factors[i]);
+ log_mpidump ("factor pi", factors[i]);
log_debug ("bit sizes: prime=%u, q=%u",
mpi_get_nbits (prime), mpi_get_nbits (q));
if (need_q_factor)
- log_debug (", q0=%u", mpi_get_nbits (q_factor));
+ log_printf (", q0=%u", mpi_get_nbits (q_factor));
for (i = 0; i < n; i++)
- log_debug (", p%d=%u", i, mpi_get_nbits (factors[i]));
- progress('\n');
+ log_printf (", p%d=%u", i, mpi_get_nbits (factors[i]));
+ log_printf ("\n");
}
if (ret_factors)
{
/* Caller wants the factors. */
- factors_new = gcry_calloc (n + 4, sizeof (*factors_new));
+ factors_new = xtrycalloc (n + 4, sizeof (*factors_new));
if (! factors_new)
{
err = gpg_err_code_from_errno (errno);
if (all_factors)
{
i = 0;
- factors_new[i++] = gcry_mpi_set_ui (NULL, 2);
+ factors_new[i++] = mpi_set_ui (NULL, 2);
factors_new[i++] = mpi_copy (q);
if (need_q_factor)
factors_new[i++] = mpi_copy (q_factor);
factors_new[i] = mpi_copy (factors[i]);
}
}
-
+
if (g)
{
/* Create a generator (start with 3). */
gcry_mpi_t tmp = mpi_alloc (mpi_get_nlimbs (prime));
gcry_mpi_t b = mpi_alloc (mpi_get_nlimbs (prime));
gcry_mpi_t pmin1 = mpi_alloc (mpi_get_nlimbs (prime));
-
+
if (need_q_factor)
err = GPG_ERR_NOT_IMPLEMENTED;
else
{
mpi_add_ui (g, g, 1);
if (DBG_CIPHER)
- {
- log_debug ("checking g:");
- gcry_mpi_dump (g);
- log_printf ("\n");
- }
+ log_printmpi ("checking g", g);
else
progress('^');
for (i = 0; i < n + 2; i++)
mpi_fdiv_q (tmp, pmin1, factors[i]);
/* No mpi_pow(), but it is okay to use this with mod
prime. */
- gcry_mpi_powm (b, g, tmp, prime);
+ mpi_powm (b, g, tmp, prime);
if (! mpi_cmp_ui (b, 1))
break;
}
if (DBG_CIPHER)
progress('\n');
- }
+ }
while (i < n + 2);
mpi_free (factors[n+1]);
mpi_free (pmin1);
}
}
-
+
if (! DBG_CIPHER)
progress ('\n');
if (is_locked && ath_mutex_unlock (&primepool_lock))
err = GPG_ERR_INTERNAL;
is_locked = 0;
- gcry_free (pool);
+ xfree (pool);
}
- gcry_free (pool_in_use);
+ xfree (pool_in_use);
if (factors)
- gcry_free (factors); /* Factors are shallow copies. */
+ xfree (factors); /* Factors are shallow copies. */
if (perms)
- gcry_free (perms);
+ xfree (perms);
mpi_free (val_2);
mpi_free (q);
{
for (i = 0; factors_new[i]; i++)
mpi_free (factors_new[i]);
- gcry_free (factors_new);
+ xfree (factors_new);
}
mpi_free (prime);
}
}
-
+/* Generate a prime used for discrete logarithm algorithms; i.e. this
+ prime will be public and no strong random is required. */
gcry_mpi_t
_gcry_generate_elg_prime (int mode, unsigned pbits, unsigned qbits,
gcry_mpi_t g, gcry_mpi_t **ret_factors)
{
- gcry_err_code_t err = GPG_ERR_NO_ERROR;
gcry_mpi_t prime = NULL;
-
- err = prime_generate_internal ((mode == 1), &prime, pbits, qbits, g,
- ret_factors, GCRY_WEAK_RANDOM, 0, 0,
- NULL, NULL);
+
+ if (prime_generate_internal ((mode == 1), &prime, pbits, qbits, g,
+ ret_factors, GCRY_WEAK_RANDOM, 0, 0,
+ NULL, NULL))
+ prime = NULL; /* (Should be NULL in the error case anyway.) */
return prime;
}
+
static gcry_mpi_t
-gen_prime (unsigned int nbits, int secret, int randomlevel,
+gen_prime (unsigned int nbits, int secret, int randomlevel,
int (*extra_check)(void *, gcry_mpi_t), void *extra_check_arg)
{
gcry_mpi_t prime, ptest, pminus1, val_2, val_3, result;
unsigned int x, step;
unsigned int count1, count2;
int *mods;
-
+
/* if ( DBG_CIPHER ) */
/* log_debug ("generate a prime of %u bits ", nbits ); */
if (nbits < 16)
log_fatal ("can't generate a prime with less than %d bits\n", 16);
- mods = gcry_xmalloc( no_of_small_prime_numbers * sizeof *mods );
+ mods = xmalloc (no_of_small_prime_numbers * sizeof *mods);
/* Make nbits fit into gcry_mpi_t implementation. */
val_2 = mpi_alloc_set_ui( 2 );
val_3 = mpi_alloc_set_ui( 3);
- prime = secret? gcry_mpi_snew ( nbits ): gcry_mpi_new ( nbits );
+ prime = secret? mpi_snew (nbits): mpi_new (nbits);
result = mpi_alloc_like( prime );
pminus1= mpi_alloc_like( prime );
ptest = mpi_alloc_like( prime );
for (;;)
{ /* try forvever */
int dotcount=0;
-
+
/* generate a random number */
- gcry_mpi_randomize( prime, nbits, randomlevel );
-
+ _gcry_mpi_randomize( prime, nbits, randomlevel );
+
/* Set high order bit to 1, set low order bit to 1. If we are
generating a secret prime we are most probably doing that
for RSA, to make sure that the modulus does have the
if (secret)
mpi_set_bit (prime, nbits-2);
mpi_set_bit(prime, 0);
-
+
/* Calculate all remainders. */
for (i=0; (x = small_prime_numbers[i]); i++ )
mods[i] = mpi_fdiv_r_ui(NULL, prime, x);
-
+
/* Now try some primes starting with prime. */
- for(step=0; step < 20000; step += 2 )
+ for(step=0; step < 20000; step += 2 )
{
/* Check against all the small primes we have in mods. */
count1++;
- for (i=0; (x = small_prime_numbers[i]); i++ )
+ for (i=0; (x = small_prime_numbers[i]); i++ )
{
while ( mods[i] + step >= x )
mods[i] -= x;
}
if ( x )
continue; /* Found a multiple of an already known prime. */
-
+
mpi_add_ui( ptest, prime, step );
/* Do a fast Fermat test now. */
count2++;
mpi_sub_ui( pminus1, ptest, 1);
- gcry_mpi_powm( result, val_2, pminus1, ptest );
+ mpi_powm( result, val_2, pminus1, ptest );
if ( !mpi_cmp_ui( result, 1 ) )
- {
+ {
/* Not composite, perform stronger tests */
if (is_prime(ptest, 5, &count2 ))
{
}
if (extra_check && extra_check (extra_check_arg, ptest))
- {
+ {
/* The extra check told us that this prime is
not of the caller's taste. */
progress ('/');
}
else
- {
+ {
/* Got it. */
mpi_free(val_2);
mpi_free(val_3);
mpi_free(result);
mpi_free(pminus1);
mpi_free(prime);
- gcry_free(mods);
- return ptest;
+ xfree(mods);
+ return ptest;
}
}
}
gcry_mpi_t result = mpi_alloc_like( prime );
gcry_mpi_t pminus1 = mpi_alloc_like( prime );
mpi_sub_ui( pminus1, prime, 1);
- gcry_mpi_powm( result, val_2, pminus1, prime );
+ mpi_powm( result, val_2, pminus1, prime );
mpi_free( pminus1 );
if ( mpi_cmp_ui( result, 1 ) )
- {
+ {
/* Is composite. */
mpi_free( result );
progress('.');
unsigned nbits = mpi_get_nbits( n );
if (steps < 5) /* Make sure that we do at least 5 rounds. */
- steps = 5;
+ steps = 5;
mpi_sub_ui( nminus1, n, 1 );
}
else
{
- gcry_mpi_randomize( x, nbits, GCRY_WEAK_RANDOM );
+ _gcry_mpi_randomize( x, nbits, GCRY_WEAK_RANDOM );
/* Make sure that the number is smaller than the prime and
keep the randomness of the high bit. */
mpi_set_highbit( x, nbits-2 );
mpi_clear_bit( x, nbits-2 );
}
- assert ( mpi_cmp( x, nminus1 ) < 0 && mpi_cmp_ui( x, 1 ) > 0 );
+ gcry_assert (mpi_cmp (x, nminus1) < 0 && mpi_cmp_ui (x, 1) > 0);
}
- gcry_mpi_powm ( y, x, q, n);
+ mpi_powm ( y, x, q, n);
if ( mpi_cmp_ui(y, 1) && mpi_cmp( y, nminus1 ) )
{
for ( j=1; j < k && mpi_cmp( y, nminus1 ); j++ )
{
- gcry_mpi_powm(y, y, a2, n);
+ mpi_powm(y, y, a2, n);
if( !mpi_cmp_ui( y, 1 ) )
goto leave; /* Not a prime. */
}
/* Given ARRAY of size N with M elements set to true produce a
modified array with the next permutation of M elements. Note, that
ARRAY is used in a one-bit-per-byte approach. To detected the last
- permutation it is useful to intialize the array with the first M
+ permutation it is useful to initialize the array with the first M
element set to true and use this test:
m_out_of_n (array, m, n);
for (i = j = 0; i < n && j < m; i++)
j++;
if (j == m)
goto ready;
-
+
This code is based on the algorithm 452 from the "Collected
Algorithms From ACM, Volume II" by C. N. Liu and D. T. Tang.
*/
/* Need to handle this simple case separately. */
if( m == 1 )
- {
+ {
for (i=0; i < n; i++ )
{
if ( array[i] )
else
k1 = k2 + 1;
}
- else
+ else
{
/* M is even. */
if( !array[n-1] )
k2 = k1 + 1;
goto leave;
}
-
+
if( !(j1 & 1) )
{
k1 = n - j1;
}
scan:
jp = n - j1 - 1;
- for (i=1; i <= jp; i++ )
+ for (i=1; i <= jp; i++ )
{
i1 = jp + 2 - i;
if( array[i1-1] )
non-zero, allocate a new, NULL-terminated array holding the prime
factors and store it in FACTORS. FLAGS might be used to influence
the prime number generation process. */
-gcry_error_t
-gcry_prime_generate (gcry_mpi_t *prime, unsigned int prime_bits,
- unsigned int factor_bits, gcry_mpi_t **factors,
- gcry_prime_check_func_t cb_func, void *cb_arg,
- gcry_random_level_t random_level,
- unsigned int flags)
+gcry_err_code_t
+_gcry_prime_generate (gcry_mpi_t *prime, unsigned int prime_bits,
+ unsigned int factor_bits, gcry_mpi_t **factors,
+ gcry_prime_check_func_t cb_func, void *cb_arg,
+ gcry_random_level_t random_level,
+ unsigned int flags)
{
- gcry_err_code_t err = GPG_ERR_NO_ERROR;
+ gcry_err_code_t rc = 0;
gcry_mpi_t *factors_generated = NULL;
gcry_mpi_t prime_generated = NULL;
unsigned int mode = 0;
if (!prime)
- return gpg_error (GPG_ERR_INV_ARG);
- *prime = NULL;
+ return GPG_ERR_INV_ARG;
+ *prime = NULL;
if (flags & GCRY_PRIME_FLAG_SPECIAL_FACTOR)
mode = 1;
/* Generate. */
- err = prime_generate_internal ((mode==1), &prime_generated, prime_bits,
- factor_bits, NULL,
- factors? &factors_generated : NULL,
- random_level, flags, 1,
- cb_func, cb_arg);
+ rc = prime_generate_internal ((mode==1), &prime_generated, prime_bits,
+ factor_bits, NULL,
+ factors? &factors_generated : NULL,
+ random_level, flags, 1,
+ cb_func, cb_arg);
- if (! err)
- if (cb_func)
- {
- /* Additional check. */
- if ( !cb_func (cb_arg, GCRY_PRIME_CHECK_AT_FINISH, prime_generated))
- {
- /* Failed, deallocate resources. */
- unsigned int i;
+ if (!rc && cb_func)
+ {
+ /* Additional check. */
+ if ( !cb_func (cb_arg, GCRY_PRIME_CHECK_AT_FINISH, prime_generated))
+ {
+ /* Failed, deallocate resources. */
+ unsigned int i;
- mpi_free (prime_generated);
- if (factors)
- {
- for (i = 0; factors_generated[i]; i++)
- mpi_free (factors_generated[i]);
- gcry_free (factors_generated);
- }
- err = GPG_ERR_GENERAL;
- }
- }
+ mpi_free (prime_generated);
+ if (factors)
+ {
+ for (i = 0; factors_generated[i]; i++)
+ mpi_free (factors_generated[i]);
+ xfree (factors_generated);
+ }
+ rc = GPG_ERR_GENERAL;
+ }
+ }
- if (! err)
+ if (!rc)
{
if (factors)
*factors = factors_generated;
*prime = prime_generated;
}
- return gcry_error (err);
+ return rc;
}
-/* Check wether the number X is prime. */
-gcry_error_t
-gcry_prime_check (gcry_mpi_t x, unsigned int flags)
+/* Check whether the number X is prime. */
+gcry_err_code_t
+_gcry_prime_check (gcry_mpi_t x, unsigned int flags)
{
- gcry_err_code_t err = GPG_ERR_NO_ERROR;
+ gcry_err_code_t rc = 0;
gcry_mpi_t val_2 = mpi_alloc_set_ui (2); /* Used by the Fermat test. */
+ (void)flags;
+
/* We use 64 rounds because the prime we are going to test is not
guaranteed to be a random one. */
if (! check_prime (x, val_2, 64, NULL, NULL))
- err = GPG_ERR_NO_PRIME;
+ rc = GPG_ERR_NO_PRIME;
mpi_free (val_2);
- return gcry_error (err);
+ return rc;
}
/* Find a generator for PRIME where the factorization of (prime-1) is
in the NULL terminated array FACTORS. Return the generator as a
newly allocated MPI in R_G. If START_G is not NULL, use this as s
atart for the search. Returns 0 on success.*/
-gcry_error_t
-gcry_prime_group_generator (gcry_mpi_t *r_g,
- gcry_mpi_t prime, gcry_mpi_t *factors,
- gcry_mpi_t start_g)
+gcry_err_code_t
+_gcry_prime_group_generator (gcry_mpi_t *r_g,
+ gcry_mpi_t prime, gcry_mpi_t *factors,
+ gcry_mpi_t start_g)
{
- gcry_mpi_t tmp = gcry_mpi_new (0);
- gcry_mpi_t b = gcry_mpi_new (0);
- gcry_mpi_t pmin1 = gcry_mpi_new (0);
- gcry_mpi_t g = start_g? gcry_mpi_copy (start_g) : gcry_mpi_set_ui (NULL, 3);
+ gcry_mpi_t tmp = mpi_new (0);
+ gcry_mpi_t b = mpi_new (0);
+ gcry_mpi_t pmin1 = mpi_new (0);
+ gcry_mpi_t g = start_g? mpi_copy (start_g) : mpi_set_ui (NULL, 3);
int first = 1;
int i, n;
if (!factors || !r_g || !prime)
- return gpg_error (GPG_ERR_INV_ARG);
- *r_g = NULL;
+ return GPG_ERR_INV_ARG;
+ *r_g = NULL;
for (n=0; factors[n]; n++)
;
if (n < 2)
- return gpg_error (GPG_ERR_INV_ARG);
+ return GPG_ERR_INV_ARG;
- /* Extra sanity check - usually disabled. */
+ /* Extra sanity check - usually disabled. */
/* mpi_set (tmp, factors[0]); */
/* for(i = 1; i < n; i++) */
/* mpi_mul (tmp, tmp, factors[i]); */
/* mpi_add_ui (tmp, tmp, 1); */
/* if (mpi_cmp (prime, tmp)) */
/* return gpg_error (GPG_ERR_INV_ARG); */
-
- gcry_mpi_sub_ui (pmin1, prime, 1);
- do
+
+ mpi_sub_ui (pmin1, prime, 1);
+ do
{
if (first)
first = 0;
else
- gcry_mpi_add_ui (g, g, 1);
-
+ mpi_add_ui (g, g, 1);
+
if (DBG_CIPHER)
- {
- log_debug ("checking g:");
- gcry_mpi_dump (g);
- log_debug ("\n");
- }
+ log_printmpi ("checking g", g);
else
progress('^');
-
+
for (i = 0; i < n; i++)
{
mpi_fdiv_q (tmp, pmin1, factors[i]);
- gcry_mpi_powm (b, g, tmp, prime);
+ mpi_powm (b, g, tmp, prime);
if (! mpi_cmp_ui (b, 1))
break;
}
progress('\n');
}
while (i < n);
-
- gcry_mpi_release (tmp);
- gcry_mpi_release (b);
- gcry_mpi_release (pmin1);
- *r_g = g;
- return 0;
+ _gcry_mpi_release (tmp);
+ _gcry_mpi_release (b);
+ _gcry_mpi_release (pmin1);
+ *r_g = g;
+
+ return 0;
}
/* Convenience function to release the factors array. */
void
-gcry_prime_release_factors (gcry_mpi_t *factors)
+_gcry_prime_release_factors (gcry_mpi_t *factors)
{
if (factors)
{
int i;
-
+
for (i=0; factors[i]; i++)
mpi_free (factors[i]);
- gcry_free (factors);
+ xfree (factors);
}
}
+
+
+\f
+/* Helper for _gcry_derive_x931_prime. */
+static gcry_mpi_t
+find_x931_prime (const gcry_mpi_t pfirst)
+{
+ gcry_mpi_t val_2 = mpi_alloc_set_ui (2);
+ gcry_mpi_t prime;
+
+ prime = mpi_copy (pfirst);
+ /* If P is even add 1. */
+ mpi_set_bit (prime, 0);
+
+ /* We use 64 Rabin-Miller rounds which is better and thus
+ sufficient. We do not have a Lucas test implementaion thus we
+ can't do it in the X9.31 preferred way of running a few
+ Rabin-Miller followed by one Lucas test. */
+ while ( !check_prime (prime, val_2, 64, NULL, NULL) )
+ mpi_add_ui (prime, prime, 2);
+
+ mpi_free (val_2);
+
+ return prime;
+}
+
+
+/* Generate a prime using the algorithm from X9.31 appendix B.4.
+
+ This function requires that the provided public exponent E is odd.
+ XP, XP1 and XP2 are the seed values. All values are mandatory.
+
+ On success the prime is returned. If R_P1 or R_P2 are given the
+ internal values P1 and P2 are saved at these addresses. On error
+ NULL is returned. */
+gcry_mpi_t
+_gcry_derive_x931_prime (const gcry_mpi_t xp,
+ const gcry_mpi_t xp1, const gcry_mpi_t xp2,
+ const gcry_mpi_t e,
+ gcry_mpi_t *r_p1, gcry_mpi_t *r_p2)
+{
+ gcry_mpi_t p1, p2, p1p2, yp0;
+
+ if (!xp || !xp1 || !xp2)
+ return NULL;
+ if (!e || !mpi_test_bit (e, 0))
+ return NULL; /* We support only odd values for E. */
+
+ p1 = find_x931_prime (xp1);
+ p2 = find_x931_prime (xp2);
+ p1p2 = mpi_alloc_like (xp);
+ mpi_mul (p1p2, p1, p2);
+
+ {
+ gcry_mpi_t r1, tmp;
+
+ /* r1 = (p2^{-1} mod p1)p2 - (p1^{-1} mod p2) */
+ tmp = mpi_alloc_like (p1);
+ mpi_invm (tmp, p2, p1);
+ mpi_mul (tmp, tmp, p2);
+ r1 = tmp;
+
+ tmp = mpi_alloc_like (p2);
+ mpi_invm (tmp, p1, p2);
+ mpi_mul (tmp, tmp, p1);
+ mpi_sub (r1, r1, tmp);
+
+ /* Fixup a negative value. */
+ if (mpi_has_sign (r1))
+ mpi_add (r1, r1, p1p2);
+
+ /* yp0 = xp + (r1 - xp mod p1*p2) */
+ yp0 = tmp; tmp = NULL;
+ mpi_subm (yp0, r1, xp, p1p2);
+ mpi_add (yp0, yp0, xp);
+ mpi_free (r1);
+
+ /* Fixup a negative value. */
+ if (mpi_cmp (yp0, xp) < 0 )
+ mpi_add (yp0, yp0, p1p2);
+ }
+
+ /* yp0 is now the first integer greater than xp with p1 being a
+ large prime factor of yp0-1 and p2 a large prime factor of yp0+1. */
+
+ /* Note that the first example from X9.31 (D.1.1) which uses
+ (Xq1 #1A5CF72EE770DE50CB09ACCEA9#)
+ (Xq2 #134E4CAA16D2350A21D775C404#)
+ (Xq #CC1092495D867E64065DEE3E7955F2EBC7D47A2D
+ 7C9953388F97DDDC3E1CA19C35CA659EDC2FC325
+ 6D29C2627479C086A699A49C4C9CEE7EF7BD1B34
+ 321DE34A#))))
+ returns an yp0 of
+ #CC1092495D867E64065DEE3E7955F2EBC7D47A2D
+ 7C9953388F97DDDC3E1CA19C35CA659EDC2FC4E3
+ BF20CB896EE37E098A906313271422162CB6C642
+ 75C1201F#
+ and not
+ #CC1092495D867E64065DEE3E7955F2EBC7D47A2D
+ 7C9953388F97DDDC3E1CA19C35CA659EDC2FC2E6
+ C88FE299D52D78BE405A97E01FD71DD7819ECB91
+ FA85A076#
+ as stated in the standard. This seems to be a bug in X9.31.
+ */
+
+ {
+ gcry_mpi_t val_2 = mpi_alloc_set_ui (2);
+ gcry_mpi_t gcdtmp = mpi_alloc_like (yp0);
+ int gcdres;
+
+ mpi_sub_ui (p1p2, p1p2, 1); /* Adjust for loop body. */
+ mpi_sub_ui (yp0, yp0, 1); /* Ditto. */
+ for (;;)
+ {
+ gcdres = mpi_gcd (gcdtmp, e, yp0);
+ mpi_add_ui (yp0, yp0, 1);
+ if (!gcdres)
+ progress ('/'); /* gcd (e, yp0-1) != 1 */
+ else if (check_prime (yp0, val_2, 64, NULL, NULL))
+ break; /* Found. */
+ /* We add p1p2-1 because yp0 is incremented after the gcd test. */
+ mpi_add (yp0, yp0, p1p2);
+ }
+ mpi_free (gcdtmp);
+ mpi_free (val_2);
+ }
+
+ mpi_free (p1p2);
+
+ progress('\n');
+ if (r_p1)
+ *r_p1 = p1;
+ else
+ mpi_free (p1);
+ if (r_p2)
+ *r_p2 = p2;
+ else
+ mpi_free (p2);
+ return yp0;
+}
+
+
+\f
+/* Generate the two prime used for DSA using the algorithm specified
+ in FIPS 186-2. PBITS is the desired length of the prime P and a
+ QBITS the length of the prime Q. If SEED is not supplied and
+ SEEDLEN is 0 the function generates an appropriate SEED. On
+ success the generated primes are stored at R_Q and R_P, the counter
+ value is stored at R_COUNTER and the seed actually used for
+ generation is stored at R_SEED and R_SEEDVALUE. */
+gpg_err_code_t
+_gcry_generate_fips186_2_prime (unsigned int pbits, unsigned int qbits,
+ const void *seed, size_t seedlen,
+ gcry_mpi_t *r_q, gcry_mpi_t *r_p,
+ int *r_counter,
+ void **r_seed, size_t *r_seedlen)
+{
+ gpg_err_code_t ec;
+ unsigned char seed_help_buffer[160/8]; /* Used to hold a generated SEED. */
+ unsigned char *seed_plus; /* Malloced buffer to hold SEED+x. */
+ unsigned char digest[160/8]; /* Helper buffer for SHA-1 digest. */
+ gcry_mpi_t val_2 = NULL; /* Helper for the prime test. */
+ gcry_mpi_t tmpval = NULL; /* Helper variable. */
+ int i;
+
+ unsigned char value_u[160/8];
+ int value_n, value_b, value_k;
+ int counter;
+ gcry_mpi_t value_w = NULL;
+ gcry_mpi_t value_x = NULL;
+ gcry_mpi_t prime_q = NULL;
+ gcry_mpi_t prime_p = NULL;
+
+ /* FIPS 186-2 allows only for 1024/160 bit. */
+ if (pbits != 1024 || qbits != 160)
+ return GPG_ERR_INV_KEYLEN;
+
+ if (!seed && !seedlen)
+ ; /* No seed value given: We are asked to generate it. */
+ else if (!seed || seedlen < qbits/8)
+ return GPG_ERR_INV_ARG;
+
+ /* Allocate a buffer to later compute SEED+some_increment. */
+ seed_plus = xtrymalloc (seedlen < 20? 20:seedlen);
+ if (!seed_plus)
+ {
+ ec = gpg_err_code_from_syserror ();
+ goto leave;
+ }
+
+ val_2 = mpi_alloc_set_ui (2);
+ value_n = (pbits - 1) / qbits;
+ value_b = (pbits - 1) - value_n * qbits;
+ value_w = mpi_new (pbits);
+ value_x = mpi_new (pbits);
+
+ restart:
+ /* Generate Q. */
+ for (;;)
+ {
+ /* Step 1: Generate a (new) seed unless one has been supplied. */
+ if (!seed)
+ {
+ seedlen = sizeof seed_help_buffer;
+ _gcry_create_nonce (seed_help_buffer, seedlen);
+ seed = seed_help_buffer;
+ }
+
+ /* Step 2: U = sha1(seed) ^ sha1((seed+1) mod 2^{qbits}) */
+ memcpy (seed_plus, seed, seedlen);
+ for (i=seedlen-1; i >= 0; i--)
+ {
+ seed_plus[i]++;
+ if (seed_plus[i])
+ break;
+ }
+ _gcry_md_hash_buffer (GCRY_MD_SHA1, value_u, seed, seedlen);
+ _gcry_md_hash_buffer (GCRY_MD_SHA1, digest, seed_plus, seedlen);
+ for (i=0; i < sizeof value_u; i++)
+ value_u[i] ^= digest[i];
+
+ /* Step 3: Form q from U */
+ _gcry_mpi_release (prime_q); prime_q = NULL;
+ ec = _gcry_mpi_scan (&prime_q, GCRYMPI_FMT_USG,
+ value_u, sizeof value_u, NULL);
+ if (ec)
+ goto leave;
+ mpi_set_highbit (prime_q, qbits-1 );
+ mpi_set_bit (prime_q, 0);
+
+ /* Step 4: Test whether Q is prime using 64 round of Rabin-Miller. */
+ if (check_prime (prime_q, val_2, 64, NULL, NULL))
+ break; /* Yes, Q is prime. */
+
+ /* Step 5. */
+ seed = NULL; /* Force a new seed at Step 1. */
+ }
+
+ /* Step 6. Note that we do no use an explicit offset but increment
+ SEED_PLUS accordingly. SEED_PLUS is currently SEED+1. */
+ counter = 0;
+
+ /* Generate P. */
+ prime_p = mpi_new (pbits);
+ for (;;)
+ {
+ /* Step 7: For k = 0,...n let
+ V_k = sha1(seed+offset+k) mod 2^{qbits}
+ Step 8: W = V_0 + V_1*2^160 +
+ ...
+ + V_{n-1}*2^{(n-1)*160}
+ + (V_{n} mod 2^b)*2^{n*160}
+ */
+ mpi_set_ui (value_w, 0);
+ for (value_k=0; value_k <= value_n; value_k++)
+ {
+ /* There is no need to have an explicit offset variable: In
+ the first round we shall have an offset of 2, this is
+ achieved by using SEED_PLUS which is already at SEED+1,
+ thus we just need to increment it once again. The
+ requirement for the next round is to update offset by N,
+ which we implictly did at the end of this loop, and then
+ to add one; this one is the same as in the first round. */
+ for (i=seedlen-1; i >= 0; i--)
+ {
+ seed_plus[i]++;
+ if (seed_plus[i])
+ break;
+ }
+ _gcry_md_hash_buffer (GCRY_MD_SHA1, digest, seed_plus, seedlen);
+
+ _gcry_mpi_release (tmpval); tmpval = NULL;
+ ec = _gcry_mpi_scan (&tmpval, GCRYMPI_FMT_USG,
+ digest, sizeof digest, NULL);
+ if (ec)
+ goto leave;
+ if (value_k == value_n)
+ mpi_clear_highbit (tmpval, value_b); /* (V_n mod 2^b) */
+ mpi_lshift (tmpval, tmpval, value_k*qbits);
+ mpi_add (value_w, value_w, tmpval);
+ }
+
+ /* Step 8 continued: X = W + 2^{L-1} */
+ mpi_set_ui (value_x, 0);
+ mpi_set_highbit (value_x, pbits-1);
+ mpi_add (value_x, value_x, value_w);
+
+ /* Step 9: c = X mod 2q, p = X - (c - 1) */
+ mpi_mul_2exp (tmpval, prime_q, 1);
+ mpi_mod (tmpval, value_x, tmpval);
+ mpi_sub_ui (tmpval, tmpval, 1);
+ mpi_sub (prime_p, value_x, tmpval);
+
+ /* Step 10: If p < 2^{L-1} skip the primality test. */
+ /* Step 11 and 12: Primality test. */
+ if (mpi_get_nbits (prime_p) >= pbits-1
+ && check_prime (prime_p, val_2, 64, NULL, NULL) )
+ break; /* Yes, P is prime, continue with Step 15. */
+
+ /* Step 13: counter = counter + 1, offset = offset + n + 1. */
+ counter++;
+
+ /* Step 14: If counter >= 2^12 goto Step 1. */
+ if (counter >= 4096)
+ goto restart;
+ }
+
+ /* Step 15: Save p, q, counter and seed. */
+/* log_debug ("fips186-2 pbits p=%u q=%u counter=%d\n", */
+/* mpi_get_nbits (prime_p), mpi_get_nbits (prime_q), counter); */
+/* log_printhex("fips186-2 seed:", seed, seedlen); */
+/* log_mpidump ("fips186-2 prime p", prime_p); */
+/* log_mpidump ("fips186-2 prime q", prime_q); */
+ if (r_q)
+ {
+ *r_q = prime_q;
+ prime_q = NULL;
+ }
+ if (r_p)
+ {
+ *r_p = prime_p;
+ prime_p = NULL;
+ }
+ if (r_counter)
+ *r_counter = counter;
+ if (r_seed && r_seedlen)
+ {
+ memcpy (seed_plus, seed, seedlen);
+ *r_seed = seed_plus;
+ seed_plus = NULL;
+ *r_seedlen = seedlen;
+ }
+
+
+ leave:
+ _gcry_mpi_release (tmpval);
+ _gcry_mpi_release (value_x);
+ _gcry_mpi_release (value_w);
+ _gcry_mpi_release (prime_p);
+ _gcry_mpi_release (prime_q);
+ xfree (seed_plus);
+ _gcry_mpi_release (val_2);
+ return ec;
+}
+
+
+\f
+/* WARNING: The code below has not yet been tested! However, it is
+ not yet used. We need to wait for FIPS 186-3 final and for test
+ vectors.
+
+ Generate the two prime used for DSA using the algorithm specified
+ in FIPS 186-3, A.1.1.2. PBITS is the desired length of the prime P
+ and a QBITS the length of the prime Q. If SEED is not supplied and
+ SEEDLEN is 0 the function generates an appropriate SEED. On
+ success the generated primes are stored at R_Q and R_P, the counter
+ value is stored at R_COUNTER and the seed actually used for
+ generation is stored at R_SEED and R_SEEDVALUE. The hash algorithm
+ used is stored at R_HASHALGO.
+
+ Note that this function is very similar to the fips186_2 code. Due
+ to the minor differences, other buffer sizes and for documentarion,
+ we use a separate function.
+*/
+gpg_err_code_t
+_gcry_generate_fips186_3_prime (unsigned int pbits, unsigned int qbits,
+ const void *seed, size_t seedlen,
+ gcry_mpi_t *r_q, gcry_mpi_t *r_p,
+ int *r_counter,
+ void **r_seed, size_t *r_seedlen,
+ int *r_hashalgo)
+{
+ gpg_err_code_t ec;
+ unsigned char seed_help_buffer[256/8]; /* Used to hold a generated SEED. */
+ unsigned char *seed_plus; /* Malloced buffer to hold SEED+x. */
+ unsigned char digest[256/8]; /* Helper buffer for SHA-1 digest. */
+ gcry_mpi_t val_2 = NULL; /* Helper for the prime test. */
+ gcry_mpi_t tmpval = NULL; /* Helper variable. */
+ int hashalgo; /* The id of the Approved Hash Function. */
+ int i;
+
+ unsigned char value_u[256/8];
+ int value_n, value_b, value_j;
+ int counter;
+ gcry_mpi_t value_w = NULL;
+ gcry_mpi_t value_x = NULL;
+ gcry_mpi_t prime_q = NULL;
+ gcry_mpi_t prime_p = NULL;
+
+ gcry_assert (sizeof seed_help_buffer == sizeof digest
+ && sizeof seed_help_buffer == sizeof value_u);
+
+ /* Step 1: Check the requested prime lengths. */
+ /* Note that due to the size of our buffers QBITS is limited to 256. */
+ if (pbits == 1024 && qbits == 160)
+ hashalgo = GCRY_MD_SHA1;
+ else if (pbits == 2048 && qbits == 224)
+ hashalgo = GCRY_MD_SHA224;
+ else if (pbits == 2048 && qbits == 256)
+ hashalgo = GCRY_MD_SHA256;
+ else if (pbits == 3072 && qbits == 256)
+ hashalgo = GCRY_MD_SHA256;
+ else
+ return GPG_ERR_INV_KEYLEN;
+
+ /* Also check that the hash algorithm is available. */
+ ec = _gcry_md_test_algo (hashalgo);
+ if (ec)
+ return ec;
+ gcry_assert (qbits/8 <= sizeof digest);
+ gcry_assert (_gcry_md_get_algo_dlen (hashalgo) == qbits/8);
+
+
+ /* Step 2: Check seedlen. */
+ if (!seed && !seedlen)
+ ; /* No seed value given: We are asked to generate it. */
+ else if (!seed || seedlen < qbits/8)
+ return GPG_ERR_INV_ARG;
+
+ /* Allocate a buffer to later compute SEED+some_increment and a few
+ helper variables. */
+ seed_plus = xtrymalloc (seedlen < sizeof seed_help_buffer?
+ sizeof seed_help_buffer : seedlen);
+ if (!seed_plus)
+ {
+ ec = gpg_err_code_from_syserror ();
+ goto leave;
+ }
+ val_2 = mpi_alloc_set_ui (2);
+ value_w = mpi_new (pbits);
+ value_x = mpi_new (pbits);
+
+ /* Step 3: n = \lceil L / outlen \rceil - 1 */
+ value_n = (pbits + qbits - 1) / qbits - 1;
+ /* Step 4: b = L - 1 - (n * outlen) */
+ value_b = pbits - 1 - (value_n * qbits);
+
+ restart:
+ /* Generate Q. */
+ for (;;)
+ {
+ /* Step 5: Generate a (new) seed unless one has been supplied. */
+ if (!seed)
+ {
+ seedlen = qbits/8;
+ gcry_assert (seedlen <= sizeof seed_help_buffer);
+ _gcry_create_nonce (seed_help_buffer, seedlen);
+ seed = seed_help_buffer;
+ }
+
+ /* Step 6: U = hash(seed) */
+ _gcry_md_hash_buffer (hashalgo, value_u, seed, seedlen);
+
+ /* Step 7: q = 2^{N-1} + U + 1 - (U mod 2) */
+ if ( !(value_u[qbits/8-1] & 0x01) )
+ {
+ for (i=qbits/8-1; i >= 0; i--)
+ {
+ value_u[i]++;
+ if (value_u[i])
+ break;
+ }
+ }
+ _gcry_mpi_release (prime_q); prime_q = NULL;
+ ec = _gcry_mpi_scan (&prime_q, GCRYMPI_FMT_USG,
+ value_u, sizeof value_u, NULL);
+ if (ec)
+ goto leave;
+ mpi_set_highbit (prime_q, qbits-1 );
+
+ /* Step 8: Test whether Q is prime using 64 round of Rabin-Miller.
+ According to table C.1 this is sufficient for all
+ supported prime sizes (i.e. up 3072/256). */
+ if (check_prime (prime_q, val_2, 64, NULL, NULL))
+ break; /* Yes, Q is prime. */
+
+ /* Step 8. */
+ seed = NULL; /* Force a new seed at Step 5. */
+ }
+
+ /* Step 11. Note that we do no use an explicit offset but increment
+ SEED_PLUS accordingly. */
+ memcpy (seed_plus, seed, seedlen);
+ counter = 0;
+
+ /* Generate P. */
+ prime_p = mpi_new (pbits);
+ for (;;)
+ {
+ /* Step 11.1: For j = 0,...n let
+ V_j = hash(seed+offset+j)
+ Step 11.2: W = V_0 + V_1*2^outlen +
+ ...
+ + V_{n-1}*2^{(n-1)*outlen}
+ + (V_{n} mod 2^b)*2^{n*outlen}
+ */
+ mpi_set_ui (value_w, 0);
+ for (value_j=0; value_j <= value_n; value_j++)
+ {
+ /* There is no need to have an explicit offset variable: In
+ the first round we shall have an offset of 1 and a j of
+ 0. This is achieved by incrementing SEED_PLUS here. For
+ the next round offset is implicitly updated by using
+ SEED_PLUS again. */
+ for (i=seedlen-1; i >= 0; i--)
+ {
+ seed_plus[i]++;
+ if (seed_plus[i])
+ break;
+ }
+ _gcry_md_hash_buffer (GCRY_MD_SHA1, digest, seed_plus, seedlen);
+
+ _gcry_mpi_release (tmpval); tmpval = NULL;
+ ec = _gcry_mpi_scan (&tmpval, GCRYMPI_FMT_USG,
+ digest, sizeof digest, NULL);
+ if (ec)
+ goto leave;
+ if (value_j == value_n)
+ mpi_clear_highbit (tmpval, value_b); /* (V_n mod 2^b) */
+ mpi_lshift (tmpval, tmpval, value_j*qbits);
+ mpi_add (value_w, value_w, tmpval);
+ }
+
+ /* Step 11.3: X = W + 2^{L-1} */
+ mpi_set_ui (value_x, 0);
+ mpi_set_highbit (value_x, pbits-1);
+ mpi_add (value_x, value_x, value_w);
+
+ /* Step 11.4: c = X mod 2q */
+ mpi_mul_2exp (tmpval, prime_q, 1);
+ mpi_mod (tmpval, value_x, tmpval);
+
+ /* Step 11.5: p = X - (c - 1) */
+ mpi_sub_ui (tmpval, tmpval, 1);
+ mpi_sub (prime_p, value_x, tmpval);
+
+ /* Step 11.6: If p < 2^{L-1} skip the primality test. */
+ /* Step 11.7 and 11.8: Primality test. */
+ if (mpi_get_nbits (prime_p) >= pbits-1
+ && check_prime (prime_p, val_2, 64, NULL, NULL) )
+ break; /* Yes, P is prime, continue with Step 15. */
+
+ /* Step 11.9: counter = counter + 1, offset = offset + n + 1.
+ If counter >= 4L goto Step 5. */
+ counter++;
+ if (counter >= 4*pbits)
+ goto restart;
+ }
+
+ /* Step 12: Save p, q, counter and seed. */
+ log_debug ("fips186-3 pbits p=%u q=%u counter=%d\n",
+ mpi_get_nbits (prime_p), mpi_get_nbits (prime_q), counter);
+ log_printhex ("fips186-3 seed", seed, seedlen);
+ log_printmpi ("fips186-3 p", prime_p);
+ log_printmpi ("fips186-3 q", prime_q);
+ if (r_q)
+ {
+ *r_q = prime_q;
+ prime_q = NULL;
+ }
+ if (r_p)
+ {
+ *r_p = prime_p;
+ prime_p = NULL;
+ }
+ if (r_counter)
+ *r_counter = counter;
+ if (r_seed && r_seedlen)
+ {
+ memcpy (seed_plus, seed, seedlen);
+ *r_seed = seed_plus;
+ seed_plus = NULL;
+ *r_seedlen = seedlen;
+ }
+ if (r_hashalgo)
+ *r_hashalgo = hashalgo;
+
+ leave:
+ _gcry_mpi_release (tmpval);
+ _gcry_mpi_release (value_x);
+ _gcry_mpi_release (value_w);
+ _gcry_mpi_release (prime_p);
+ _gcry_mpi_release (prime_q);
+ xfree (seed_plus);
+ _gcry_mpi_release (val_2);
+ return ec;
+}
projects / libgcrypt.git / blobdiff