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Add public function generating private keys

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This will be useful for restartable ECDH and ECDSA. Currently they call
mbedtls_ecp_gen_keypair(); one could make that one restartable, but that means
adding its own sub-context, while ECDH and ECDSA (will) have their own
contexts already, so switching to this saves one extra context.
This commit is contained in:
Manuel Pégourié-Gonnard 2017-04-20 15:37:46 +02:00
parent 1631d63d0c
commit a7937f9967
2 changed files with 39 additions and 11 deletions
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16
include/mbedtls/ecp.h
View File

@ -727,6 +727,22 @@ int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp, const mbedtls_ecp_po
*/
int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi *d );
/**
* \brief Generate a private key
*
* \param grp ECP group
* \param d Destination MPI (secret part)
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \return 0 if successful,
* or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
*/
int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp,
mbedtls_mpi *d,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/**
* \brief Generate a keypair with configurable base point
*

34
library/ecp.c
View File

@ -2495,15 +2495,14 @@ int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi *
}
/*
* Generate a keypair with configurable base point
* Generate a private key
*/
int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
const mbedtls_ecp_point *G,
mbedtls_mpi *d, mbedtls_ecp_point *Q,
int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp,
mbedtls_mpi *d,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
size_t n_size = ( grp->nbits + 7 ) / 8;
#if defined(ECP_MONTGOMERY)
@ -2528,8 +2527,8 @@ int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 1, 0 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 2, 0 ) );
}
else
#endif /* ECP_MONTGOMERY */
#if defined(ECP_SHORTWEIERSTRASS)
if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
{
@ -2565,15 +2564,28 @@ int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
while( mbedtls_mpi_cmp_int( d, 1 ) < 0 ||
mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 );
}
else
#endif /* ECP_SHORTWEIERSTRASS */
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
cleanup:
if( ret != 0 )
return( ret );
return( ret );
}
return( mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ) );
/*
* Generate a keypair with configurable base point
*/
int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
const mbedtls_ecp_point *G,
mbedtls_mpi *d, mbedtls_ecp_point *Q,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) );
MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ) );
cleanup:
return( ret );
}
/*