Add functions to psa_util module to convert EC public keys

This commit is contained in:
Hanno Becker 2019-01-07 15:36:51 +00:00
parent 9c99dc862c
commit f75f912c31

View file

@ -43,6 +43,8 @@
#include "pk.h"
#include "oid.h"
#include <string.h>
/* Translations for symmetric crypto. */
static inline psa_key_type_t mbedtls_psa_translate_cipher_type(
@ -352,6 +354,48 @@ static inline psa_ecc_curve_t mbedtls_psa_parse_tls_ecc_group(
return( (psa_ecc_curve_t) tls_ecc_grp_reg_id );
}
/* This function takes a buffer holding an EC public key
* exported through psa_export_public_key(), and converts
* it into an ECPoint structure to be put into a ClientKeyExchange
* message in an ECDHE exchange.
*
* Both the present and the foreseeable future format of EC public keys
* used by PSA have the ECPoint structure contained in the exported key
* as a subbuffer, and the function merely selects this subbuffer instead
* of making a copy.
*/
static inline int mbedtls_psa_tls_psa_ec_to_ecpoint( unsigned char *src,
size_t srclen,
unsigned char **dst,
size_t *dstlen )
{
*dst = src;
*dstlen = srclen;
return( 0 );
}
/* This function takes a buffer holding an ECPoint structure
* (as contained in a TLS ServerKeyExchange message for ECDHE
* exchanges) and converts it into a format that the PSA key
* agreement API understands.
*/
static inline int mbedtls_psa_tls_ecpoint_to_psa_ec( psa_ecc_curve_t curve,
unsigned char const *src,
size_t srclen,
unsigned char *dst,
size_t dstlen,
size_t *olen )
{
((void) curve);
if( srclen > dstlen )
return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
memcpy( dst, src, srclen );
*olen = srclen;
return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#endif /* MBEDTLS_PSA_UTIL_H */