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improve key generation

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This commit is contained in:
NIIBE Yutaka
2013-09-27 17:31:26 +09:00
parent 34f2fa5380
commit f207c4ec49
3 changed files with 83 additions and 46 deletions
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117
polarssl/library/bignum.c
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@@ -1785,6 +1785,7 @@ static const int small_prime[] =
/*
* Miller-Rabin primality test (HAC 4.24)
*/
static
int mpi_is_prime( mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
@@ -1805,6 +1806,7 @@ int mpi_is_prime( mpi *X,
xs = X->s; X->s = 1;
#if 0
/*
* test trivial factors first
*/
@@ -1823,6 +1825,7 @@ int mpi_is_prime( mpi *X,
if( r == 0 )
return( POLARSSL_ERR_MPI_NOT_ACCEPTABLE );
}
#endif
/*
* W = |X| - 1
@@ -1900,72 +1903,94 @@ cleanup:
return( ret );
}
/*
* Value M: multiply all primes up to 691
*/
#define M_LIMBS 31
#define M_SIZE 121
static const t_uint limbs_M[] = { /* Little endian */
0xC4A41A2E, 0xE5EFDDEE, 0x421A588E, 0xB0FB4F7B,
0xA007B213, 0x384159E3, 0xDB479E8A, 0x9781B78D,
0xEECE412F, 0x01FF1B61, 0xF5ACB721, 0x3918A8AA,
0x80F6271D, 0x4E6314A2, 0x432BF67F, 0x53AF4FEB,
0x85FE4727, 0x2CDC5CB4, 0xC4903782, 0x0FE374A0,
0xCE53E956, 0x640F5175, 0x66A12FC3, 0xD42CF844,
0xB4C79D3F, 0x0CCFB001, 0x8FC4A724, 0x7EE7A682,
0x831E885C, 0xD987593B, 0x00000002,
};
static const mpi M[1] = {{ 1, M_LIMBS, (t_uint *)limbs_M }};
/*
* MAX_A
*/
#define MAX_A_LIMBS 2
#define MAX_A_SIZE 8
static const t_uint limbs_MAX_A[] = { /* Little endian */
0xFE294A0D, 0x59D555BF
};
static const mpi MAX_A[1] = {{ 1, MAX_A_LIMBS, (t_uint *)limbs_MAX_A }};
/*
* Prime number generation
*
* Special version for 1024-bit only. Ignores DH_FLAG.
*/
int mpi_gen_prime( mpi *X, size_t nbits, int dh_flag,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
size_t k, n;
mpi Y;
int ret;
mpi B[1], G[1];
if( nbits < 3 || nbits > POLARSSL_MPI_MAX_BITS )
return( POLARSSL_ERR_MPI_BAD_INPUT_DATA );
(void)dh_flag;
if (nbits != 1024)
return POLARSSL_ERR_MPI_BAD_INPUT_DATA;
mpi_init( &Y );
mpi_init ( B ); mpi_init ( G );
n = BITS_TO_LIMBS( nbits );
MPI_CHK( mpi_fill_random( X, n * ciL, f_rng, p_rng ) );
k = mpi_msb( X );
if( k < nbits ) MPI_CHK( mpi_shift_l( X, nbits - k ) );
if( k > nbits ) MPI_CHK( mpi_shift_r( X, k - nbits ) );
X->p[0] |= 3;
if( dh_flag == 0 )
/*
* Get random value 1 to M-1 avoiding bias, and proceed when it is
* coprime to all small primes.
*/
do
{
while( ( ret = mpi_is_prime( X, f_rng, p_rng ) ) != 0 )
{
if( ret != POLARSSL_ERR_MPI_NOT_ACCEPTABLE )
goto cleanup;
MPI_CHK ( mpi_fill_random ( B, M_SIZE, f_rng, p_rng ) );
B->p[0] |= 0x1;
B->p[M_LIMBS - 1] &= 0x3;
if (mpi_cmp_abs (B, M) >= 0)
continue;
MPI_CHK( mpi_add_int( X, X, 2 ) );
}
MPI_CHK ( mpi_gcd ( G, B, M ) );
}
else
while (mpi_cmp_int ( G, 1 ) != 0);
/*
* Get random value 0 to MAX_A avoiding bias, comput P with the value,
* and check if it's prime.
*/
while (1)
{
MPI_CHK( mpi_sub_int( &Y, X, 1 ) );
MPI_CHK( mpi_shift_r( &Y, 1 ) );
MPI_CHK( mpi_fill_random( X, MAX_A_SIZE, f_rng, p_rng ) );
X->p[MAX_A_LIMBS - 1] &= 0x7fffffff;
if (mpi_cmp_abs (X, MAX_A) > 0)
continue;
MPI_CHK ( mpi_mul_mpi (X, X, M) );
MPI_CHK ( mpi_add_abs ( X, X, B ) );
while( 1 )
{
if( ( ret = mpi_is_prime( X, f_rng, p_rng ) ) == 0 )
{
if( ( ret = mpi_is_prime( &Y, f_rng, p_rng ) ) == 0 )
break;
if( ret != POLARSSL_ERR_MPI_NOT_ACCEPTABLE )
goto cleanup;
}
if( ret != POLARSSL_ERR_MPI_NOT_ACCEPTABLE )
goto cleanup;
MPI_CHK( mpi_add_int( &Y, X, 1 ) );
MPI_CHK( mpi_add_int( X, X, 2 ) );
MPI_CHK( mpi_shift_r( &Y, 1 ) );
}
ret = mpi_is_prime ( X, f_rng, p_rng );
if (ret == 0 || ret != POLARSSL_ERR_MPI_NOT_ACCEPTABLE)
break;
}
cleanup:
mpi_free( &Y );
mpi_free ( B ); mpi_free ( G );
return( ret );
return ret;
}
#endif