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Add #ifdef's for curve types

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This commit is contained in:
Manuel Pégourié-Gonnard 2013-12-05 10:06:06 +01:00
parent 7c94d8bcab
commit d962273594
1 changed files with 58 additions and 29 deletions
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87
library/ecp.c
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@ -1603,32 +1603,16 @@ int ecp_mul( ecp_group *grp, ecp_point *R,
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
}
#if defined(POLARSSL_ECP_SHORT_WEIERSTRASS)
/*
* Check that a point is valid as a public key
* Check that an affine point is valid as a public key,
* short weierstrass curves (SEC1 3.2.3.1)
*/
// TODO
int ecp_check_pubkey( const ecp_group *grp, const ecp_point *pt )
static int ecp_check_pubkey_sw( const ecp_group *grp, const ecp_point *pt )
{
int ret;
mpi YY, RHS;
/* Must use affine coordinates */
if( mpi_cmp_int( &pt->Z, 1 ) != 0 )
return( POLARSSL_ERR_ECP_INVALID_KEY );
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_MONTGOMERY )
{
/* [M255 p. 5] Just check X is the correct number of bytes */
if( mpi_size( &pt->X ) > ( grp->nbits + 7 ) / 8 )
return( POLARSSL_ERR_ECP_INVALID_KEY );
return( 0 );
}
/*
* Ok, so we have a short Weierstrass curve as in SEC1 3.2.3.1
*/
/* pt coordinates must be normalized for our checks */
if( mpi_cmp_int( &pt->X, 0 ) < 0 ||
mpi_cmp_int( &pt->Y, 0 ) < 0 ||
@ -1638,12 +1622,6 @@ int ecp_check_pubkey( const ecp_group *grp, const ecp_point *pt )
mpi_init( &YY ); mpi_init( &RHS );
if( mpi_cmp_int( &pt->X, 0 ) < 0 ||
mpi_cmp_int( &pt->Y, 0 ) < 0 ||
mpi_cmp_mpi( &pt->X, &grp->P ) >= 0 ||
mpi_cmp_mpi( &pt->Y, &grp->P ) >= 0 )
return( POLARSSL_ERR_ECP_INVALID_KEY );
/*
* YY = Y^2
* RHS = X (X^2 + A) + B = X^3 + A X + B
@ -1663,12 +1641,49 @@ cleanup:
return( ret );
}
#endif /* POLARSSL_ECP_SHORT_WEIERSTRASS */
#if defined(POLARSSL_ECP_MONTGOMERY)
/*
* Check validity of a public key for Montgomery curves with x-only schemes
*/
static int ecp_check_pubkey_mx( const ecp_group *grp, const ecp_point *pt )
{
/* [M255 p. 5] Just check X is the correct number of bytes */
if( mpi_size( &pt->X ) > ( grp->nbits + 7 ) / 8 )
return( POLARSSL_ERR_ECP_INVALID_KEY );
return( 0 );
}
#endif /* POLARSSL_ECP_MONTGOMERY */
/*
* Check that a point is valid as a public key
*/
int ecp_check_pubkey( const ecp_group *grp, const ecp_point *pt )
{
/* Must use affine coordinates */
if( mpi_cmp_int( &pt->Z, 1 ) != 0 )
return( POLARSSL_ERR_ECP_INVALID_KEY );
#if defined(POLARSSL_ECP_MONTGOMERY)
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_MONTGOMERY )
return( ecp_check_pubkey_mx( grp, pt ) );
#endif
#if defined(POLARSSL_ECP_SHORT_WEIERSTRASS)
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_SHORT_WEIERSTRASS )
return( ecp_check_pubkey_sw( grp, pt ) );
#endif
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
}
/*
* Check that an mpi is valid as a private key
*/
int ecp_check_privkey( const ecp_group *grp, const mpi *d )
{
#if defined(POLARSSL_ECP_MONTGOMERY)
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_MONTGOMERY )
{
/* see [M255] page 5 */
@ -1677,16 +1692,23 @@ int ecp_check_privkey( const ecp_group *grp, const mpi *d )
mpi_get_bit( d, 2 ) != 0 ||
mpi_msb( d ) - 1 != grp->nbits ) /* mpi_msb is one-based! */
return( POLARSSL_ERR_ECP_INVALID_KEY );
else
return( 0 );
}
else
#endif
#if defined(POLARSSL_ECP_SHORT_WEIERSTRASS)
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_SHORT_WEIERSTRASS )
{
/* see SEC1 3.2 */
if( mpi_cmp_int( d, 1 ) < 0 ||
mpi_cmp_mpi( d, &grp->N ) >= 0 )
return( POLARSSL_ERR_ECP_INVALID_KEY );
else
return( 0 );
}
#endif
return( 0 );
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
}
/*
@ -1696,9 +1718,9 @@ int ecp_gen_keypair( ecp_group *grp, mpi *d, ecp_point *Q,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int count = 0;
size_t n_size = (grp->nbits + 7) / 8;
#if defined(POLARSSL_ECP_MONTGOMERY)
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_MONTGOMERY )
{
/* [M225] page 5 */
@ -1719,8 +1741,12 @@ int ecp_gen_keypair( ecp_group *grp, mpi *d, ecp_point *Q,
mpi_set_bit( d, 2, 0 );
}
else
#endif
#if defined(POLARSSL_ECP_SHORT_WEIERSTRASS)
if( ecp_get_type( grp ) == POLARSSL_ECP_TYPE_SHORT_WEIERSTRASS )
{
/* SEC1 3.2.1: Generate d such that 1 <= n < N */
int count = 0;
do
{
mpi_fill_random( d, n_size, f_rng, p_rng );
@ -1733,6 +1759,9 @@ int ecp_gen_keypair( ecp_group *grp, mpi *d, ecp_point *Q,
}
while( mpi_cmp_int( d, 1 ) < 0 );
}
else
#endif
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
return( ecp_mul( grp, Q, d, &grp->G, f_rng, p_rng ) );
}