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Split mpi_is_prime() and make its first arg const

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Manuel Pégourié-Gonnard 2013-11-22 18:39:18 +01:00
parent 0160eacc82
commit 378fb4b70a
3 changed files with 69 additions and 31 deletions
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2
include/polarssl/bignum.h
View file

@ -653,7 +653,7 @@ int mpi_inv_mod( mpi *X, const mpi *A, const mpi *N );
* POLARSSL_ERR_MPI_MALLOC_FAILED if memory allocation failed,
* POLARSSL_ERR_MPI_NOT_ACCEPTABLE if X is not prime
*/
int mpi_is_prime( mpi *X,
int mpi_is_prime( const mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );

86
library/bignum.c
View file

@ -1797,40 +1797,27 @@ static const int small_prime[] =
};
/*
* Miller-Rabin primality test (HAC 4.24)
* Small divisors test (X must be positive)
*
* Return values:
* 0: no small factor (possible prime, more tests needed)
* 1: certain prime
* POLARSSL_ERR_MPI_NOT_ACCEPTABLE: certain non-prime
* other negative: error
*/
int mpi_is_prime( mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
static int mpi_check_small_factors( const mpi *X )
{
int ret, xs;
size_t i, j, n, s;
mpi W, R, T, A, RR;
int ret = 0;
size_t i;
t_uint r;
if( mpi_cmp_int( X, 0 ) == 0 ||
mpi_cmp_int( X, 1 ) == 0 )
return( POLARSSL_ERR_MPI_NOT_ACCEPTABLE );
if( mpi_cmp_int( X, 2 ) == 0 )
return( 0 );
mpi_init( &W ); mpi_init( &R ); mpi_init( &T ); mpi_init( &A );
mpi_init( &RR );
xs = X->s; X->s = 1;
/*
* test trivial factors first
*/
if( ( X->p[0] & 1 ) == 0 )
return( POLARSSL_ERR_MPI_NOT_ACCEPTABLE );
for( i = 0; small_prime[i] > 0; i++ )
{
t_uint r;
if( mpi_cmp_int( X, small_prime[i] ) <= 0 )
return( 0 );
return( 1 );
MPI_CHK( mpi_mod_int( &r, X, small_prime[i] ) );
@ -1838,6 +1825,24 @@ int mpi_is_prime( mpi *X,
return( POLARSSL_ERR_MPI_NOT_ACCEPTABLE );
}
cleanup:
return( ret );
}
/*
* Miller-Rabin pseudo-primality test (HAC 4.24)
*/
static int mpi_miller_rabin( const mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
size_t i, j, n, s;
mpi W, R, T, A, RR;
mpi_init( &W ); mpi_init( &R ); mpi_init( &T ); mpi_init( &A );
mpi_init( &RR );
/*
* W = |X| - 1
* R = W >> lsb( W )
@ -1905,15 +1910,40 @@ int mpi_is_prime( mpi *X,
}
cleanup:
X->s = xs;
mpi_free( &W ); mpi_free( &R ); mpi_free( &T ); mpi_free( &A );
mpi_free( &RR );
return( ret );
}
/*
* Pseudo-primality test: small factors, then Miller-Rabin
*/
int mpi_is_prime( const mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
const mpi XX = { 1, X->n, X->p }; /* Abs(X) */
if( mpi_cmp_int( &XX, 0 ) == 0 ||
mpi_cmp_int( &XX, 1 ) == 0 )
return( POLARSSL_ERR_MPI_NOT_ACCEPTABLE );
if( mpi_cmp_int( &XX, 2 ) == 0 )
return( 0 );
if( ( ret = mpi_check_small_factors( &XX ) ) != 0 )
{
if( ret == 1 )
return( 0 );
return( ret );
}
return( mpi_miller_rabin( &XX, f_rng, p_rng ) );
}
/*
* Prime number generation
*/

12
tests/suites/test_suite_mpi.data
View file

@ -504,11 +504,19 @@ Base test mpi_is_prime #8
depends_on:POLARSSL_GENPRIME
mpi_is_prime:10:"47":0
Test mpi_is_prime #1
Test mpi_is_prime #1a
depends_on:POLARSSL_GENPRIME
mpi_is_prime:10:"83726728883146151979668243326097049289208482987685965276439157162337476477581":POLARSSL_ERR_MPI_NOT_ACCEPTABLE
Test mpi_is_prime #1b
depends_on:POLARSSL_GENPRIME
mpi_is_prime:10:"81248637410584921454869308488899267096530643632730258201256092582281263244641":POLARSSL_ERR_MPI_NOT_ACCEPTABLE
Test mpi_is_prime #2a
depends_on:POLARSSL_GENPRIME
mpi_is_prime:10:"827131507221654563937832686696200995595835694437983658840870036586124168186967796809117749047430768825822857042432722828096779098498192459819306321073968735177531164565305635281198148032612029767584644305912099":0
Test mpi_is_prime #2
Test mpi_is_prime #2b
depends_on:POLARSSL_GENPRIME
mpi_is_prime:10:"827131507221654563937832686696200995595835694437983658840870036586124168186967796809117749047430768825822857042432722828096779098498192459819306321073968735177531164565305635281198148032612029767584644305912001":POLARSSL_ERR_MPI_NOT_ACCEPTABLE