Some operations are not supported with Curve25519

This commit is contained in:
Manuel Pégourié-Gonnard 2013-12-04 20:52:04 +01:00
parent 3d7053a2bb
commit 97871ef236
3 changed files with 20 additions and 0 deletions

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@ -444,6 +444,9 @@ int ecp_tls_write_group( const ecp_group *grp, size_t *olen,
*
* \return 0 if successful,
* POLARSSL_ERR_MPI_MALLOC_FAILED if memory allocation failed
*
* \note This function does not support Montgomery curves, such as
* Curve25519.
*/
int ecp_add( const ecp_group *grp, ecp_point *R,
const ecp_point *P, const ecp_point *Q );
@ -458,6 +461,9 @@ int ecp_add( const ecp_group *grp, ecp_point *R,
*
* \return 0 if successful,
* POLARSSL_ERR_MPI_MALLOC_FAILED if memory allocation failed
*
* \note This function does not support Montgomery curves, such as
* Curve25519.
*/
int ecp_sub( const ecp_group *grp, ecp_point *R,
const ecp_point *P, const ecp_point *Q );

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@ -59,6 +59,10 @@ int ecdsa_sign( ecp_group *grp, mpi *r, mpi *s,
ecp_point R;
mpi k, e;
/* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
if( grp->N.p == NULL )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
ecp_point_init( &R );
mpi_init( &k );
mpi_init( &e );
@ -129,6 +133,10 @@ int ecdsa_verify( ecp_group *grp,
ecp_point_init( &R ); ecp_point_init( &P );
mpi_init( &e ); mpi_init( &s_inv ); mpi_init( &u1 ); mpi_init( &u2 );
/* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
if( grp->N.p == NULL )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
/*
* Step 1: make sure r and s are in range 1..n-1
*/

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@ -946,6 +946,9 @@ int ecp_add( const ecp_group *grp, ecp_point *R,
{
int ret;
if( ecp_is_montgomery( grp ) )
return( POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE );
MPI_CHK( ecp_add_mixed( grp, R, P, Q ) );
MPI_CHK( ecp_normalize_jac( grp, R ) );
@ -965,6 +968,9 @@ int ecp_sub( const ecp_group *grp, ecp_point *R,
ecp_point_init( &mQ );
if( ecp_is_montgomery( grp ) )
return( POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE );
/* mQ = - Q */
ecp_copy( &mQ, Q );
if( mpi_cmp_int( &mQ.Y, 0 ) != 0 )