security-and-privacy/gnupg
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See ChangeLog: Tue May 4 15:49:29 CEST 1999 Werner Koch

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This commit is contained in:
Werner Koch 1999-05-04 13:55:41 +00:00
parent 88374b2ab3
commit e5a79b2da8
9 changed files with 90 additions and 54 deletions
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93
cipher/primegen.c
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@ -34,7 +34,7 @@
static int no_of_small_prime_numbers;
static MPI gen_prime( unsigned nbits, int mode, int randomlevel );
static int check_prime( MPI prime );
static int check_prime( MPI prime, MPI val_2 );
static int is_prime( MPI n, int steps, int *count );
static void m_out_of_n( char *array, int m, int n );
@ -89,6 +89,7 @@ generate_elg_prime( int mode, unsigned pbits, unsigned qbits,
int count1, count2;
unsigned nprime;
unsigned req_qbits = qbits; /* the requested q bits size */
MPI val_2 = mpi_alloc_set_ui( 2 );
/* find number of needed prime factors */
for(n=1; (pbits - qbits - 1) / n >= qbits; n++ )
@ -186,7 +187,7 @@ generate_elg_prime( int mode, unsigned pbits, unsigned qbits,
}
else
count2 = 0;
} while( !(nprime == pbits && check_prime( prime )) );
} while( !(nprime == pbits && check_prime( prime, val_2 )) );
if( DBG_CIPHER ) {
putc('\n', stderr);
@ -261,6 +262,7 @@ generate_elg_prime( int mode, unsigned pbits, unsigned qbits,
mpi_free( pool[i] );
m_free( pool );
m_free(perms);
mpi_free(val_2);
return prime;
}
@ -270,7 +272,7 @@ static MPI
gen_prime( unsigned nbits, int secret, int randomlevel )
{
unsigned nlimbs;
MPI prime, val_2, val_3, result;
MPI prime, ptest, pminus1, val_2, val_3, result;
int i;
unsigned x, step;
unsigned count1, count2;
@ -286,19 +288,17 @@ gen_prime( unsigned nbits, int secret, int randomlevel )
mods = m_alloc( no_of_small_prime_numbers * sizeof *mods );
/* make nbits fit into MPI implementation */
nlimbs = (nbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB;
val_2 = mpi_alloc( nlimbs );
mpi_set_ui(val_2, 2);
val_3 = mpi_alloc( nlimbs );
mpi_set_ui(val_3, 3);
result = mpi_alloc( nlimbs );
val_2 = mpi_alloc_set_ui( 2 );
val_3 = mpi_alloc_set_ui( 3);
prime = secret? mpi_alloc_secure( nlimbs ): mpi_alloc( nlimbs );
result = mpi_alloc_like( prime );
pminus1= mpi_alloc_like( prime );
ptest = mpi_alloc_like( prime );
count1 = count2 = 0;
/* enter (endless) loop */
for(;;) {
for(;;) { /* try forvever */
int dotcount=0;
/* generate a random number */
/*mpi_set_bytes( prime, nbits, get_random_byte, randomlevel );*/
{ char *p = get_random_bits( nbits, randomlevel, secret );
mpi_set_buffer( prime, p, (nbits+7)/8, 0 );
m_free(p);
@ -312,6 +312,7 @@ gen_prime( unsigned nbits, int secret, int randomlevel )
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 ) {
/* check against all the small primes we have in mods */
count1++;
@ -322,40 +323,31 @@ gen_prime( unsigned nbits, int secret, int randomlevel )
break;
}
if( x )
continue; /* found a multiple of a already known prime */
continue; /* found a multiple of an already known prime */
mpi_add_ui( prime, prime, step );
mpi_add_ui( ptest, prime, step );
#if 0
/* do a Fermat test */
/* do a faster Fermat test */
count2++;
mpi_powm( result, val_2, prime, prime );
if( mpi_cmp_ui(result, 2) )
continue; /* stepping (fermat test failed) */
fputc('+', stderr);
#endif
/* perform stronger tests */
if( is_prime(prime, 5, &count2 ) ) {
if( !mpi_test_bit( prime, nbits-1 ) ) {
if( 0 && DBG_CIPHER ) {
mpi_sub_ui( pminus1, ptest, 1);
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( !mpi_test_bit( ptest, nbits-1 ) ) {
fputc('\n', stderr);
log_debug("overflow in prime generation\n");
break; /* step loop, cont with a new prime */
break; /* step loop, continue with a new prime */
}
}
if( 0 && DBG_CIPHER ) {
log_debug("performed %u simple and %u stronger tests\n",
count1, count2 );
log_mpidump("found prime: ", prime );
mpi_free(val_2);
mpi_free(val_3);
mpi_free(result);
mpi_free(pminus1);
mpi_free(prime);
m_free(mods);
return ptest;
}
mpi_free(val_2);
mpi_free(val_3);
mpi_free(result);
m_free(mods);
return prime;
}
if( ++dotcount == 10 ) {
fputc('.', stderr);
@ -370,7 +362,7 @@ gen_prime( unsigned nbits, int secret, int randomlevel )
* Returns: true if this may be a prime
*/
static int
check_prime( MPI prime )
check_prime( MPI prime, MPI val_2 )
{
int i;
unsigned x;
@ -382,19 +374,20 @@ check_prime( MPI prime )
return 0;
}
#if 0
result = mpi_alloc( mpi_get_nlimbs(prime) );
val_2 = mpi_alloc_set_ui( 2 );
mpi_powm( result, val_2, prime, prime );
if( mpi_cmp_ui(result, 2) ) {
mpi_free(result);
mpi_free(val_2);
return 0;
/* a quick fermat test */
{
MPI result = mpi_alloc_like( prime );
MPI pminus1 = mpi_alloc_like( prime );
mpi_sub_ui( pminus1, prime, 1);
mpi_powm( result, val_2, pminus1, prime );
mpi_free( pminus1 );
if( mpi_cmp_ui( result, 1 ) ) { /* if composite */
mpi_free( result );
fputc('.', stderr);
return 0;
}
mpi_free( result );
}
mpi_free(result);
mpi_free(val_2);
fputc('+', stderr);
#endif
/* perform stronger tests */
if( is_prime(prime, 5, &count ) )