Add Curve25519 to known groups

This commit is contained in:
Manuel Pégourié-Gonnard 2013-12-03 14:12:26 +01:00
parent 3afa07f05b
commit 661536677b
3 changed files with 44 additions and 1 deletions

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@ -248,6 +248,10 @@
#define POLARSSL_ECP_DP_BP256R1_ENABLED
#define POLARSSL_ECP_DP_BP384R1_ENABLED
#define POLARSSL_ECP_DP_BP512R1_ENABLED
//#define POLARSSL_ECP_DP_M221_ENABLED // Not implemented yet!
#define POLARSSL_ECP_DP_M255_ENABLED
//#define POLARSSL_ECP_DP_M383_ENABLED // Not implemented yet!
//#define POLARSSL_ECP_DP_M511_ENABLED // Not implemented yet!
/**
* \def POLARSSL_ECP_NIST_OPTIM

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@ -64,10 +64,16 @@ typedef enum
POLARSSL_ECP_DP_BP256R1, /*!< 256-bits Brainpool curve */
POLARSSL_ECP_DP_BP384R1, /*!< 384-bits Brainpool curve */
POLARSSL_ECP_DP_BP512R1, /*!< 512-bits Brainpool curve */
POLARSSL_ECP_DP_M221, /*!< (not implemented yet) */
POLARSSL_ECP_DP_M255, /*!< Curve25519 */
POLARSSL_ECP_DP_M383, /*!< (not implemented yet) */
POLARSSL_ECP_DP_M511, /*!< (not implemented yet) */
} ecp_group_id;
/**
* Number of supported curves (plus one for NONE)
* Number of supported curves (plus one for NONE).
*
* (Montgomery curves excluded for now.)
*/
#define POLARSSL_ECP_DP_MAX 9

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@ -341,11 +341,39 @@ static int ecp_mod_p521( mpi * );
G ## _gy, sizeof( G ## _gy ), \
G ## _n, sizeof( G ## _n ) )
/*
* Specialized function for creating the Curve25519 group
*/
static int ecp_use_curve25519( ecp_group *grp )
{
int ret;
/* Actually ( A + 2 ) / 4 */
MPI_CHK( mpi_read_string( &grp->A, 16, "01DB42" ) );
/* P = 2^255 - 19 */
MPI_CHK( mpi_lset( &grp->P, 1 ) );
MPI_CHK( mpi_shift_l( &grp->P, 255 ) );
MPI_CHK( mpi_sub_int( &grp->P, &grp->P, 19 ) );
grp->pbits = mpi_msb( &grp->P );
/* Actually, the required msb for private keys */
grp->nbits = 254;
cleanup:
if( ret != 0 )
ecp_group_free( grp );
return( ret );
}
/*
* Set a group using well-known domain parameters
*/
int ecp_use_known_dp( ecp_group *grp, ecp_group_id id )
{
ecp_group_free( grp );
grp->id = id;
switch( id )
@ -395,6 +423,11 @@ int ecp_use_known_dp( ecp_group *grp, ecp_group_id id )
return( LOAD_GROUP( brainpoolP512r1 ) );
#endif /* POLARSSL_ECP_DP_BP512R1_ENABLED */
#if defined(POLARSSL_ECP_DP_M255_ENABLED)
case POLARSSL_ECP_DP_M255:
return( ecp_use_curve25519( grp ) );
#endif /* POLARSSL_ECP_DP_M255_ENABLED */
default:
ecp_group_free( grp );
return( POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE );