pk: adding a new field to store the public key in raw format
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index ec2a251..9b2cab8 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -202,6 +202,21 @@
#define MBEDTLS_PK_CAN_ECDH
#endif
+/* Helper to define which fields in the pk_context structure below should be
+ * used for EC keys: legacy ecp_keypair or the raw (PSA friendly) format.
+ * It should be noticed that this only affect how data is stored, not which
+ * functions are used for various operations. The overall picture looks like
+ * this:
+ * - if ECP_C is defined then use legacy functions
+ * - if USE_PSA is defined and
+ * - if ECP_C then use ecp_keypair structure, convert data to a PSA friendly
+ * format and use PSA functions
+ * - if !ECP_C then use new raw data and PSA functions directly.
+ */
+#if defined(MBEDTLS_USE_PSA_CRYPTO) && !defined(MBEDTLS_ECP_C)
+#define MBEDTLS_PK_USE_PSA_EC_DATA
+#endif /* MBEDTLS_USE_PSA_CRYPTO && !MBEDTLS_ECP_C */
+
/**
* \brief Types for interfacing with the debug module
*/
@@ -232,19 +247,49 @@
*/
typedef struct mbedtls_pk_info_t mbedtls_pk_info_t;
+#define MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN \
+ PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS)
/**
* \brief Public key container
- *
- * \note The priv_id is guarded by MBEDTLS_PSA_CRYPTO_C and not
- * by MBEDTLS_USE_PSA_CRYPTO because it can be used also
- * in mbedtls_pk_sign_ext for RSA keys.
*/
typedef struct mbedtls_pk_context {
const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info); /**< Public key information */
void *MBEDTLS_PRIVATE(pk_ctx); /**< Underlying public key context */
+ /* When MBEDTLS_PSA_CRYPTO_C is enabled then the following priv_id field is
+ * used to store the ID of the opaque key. Differently from the raw public
+ * key management below, in this case there is no counterpart in the pk_ctx
+ * field to work in parallel with.
+ * This priv_id is guarded by MBEDTLS_PSA_CRYPTO_C and not by
+ * MBEDTLS_USE_PSA_CRYPTO because it can be used also in mbedtls_pk_sign_ext
+ * for RSA keys. */
#if defined(MBEDTLS_PSA_CRYPTO_C)
mbedtls_svc_key_id_t MBEDTLS_PRIVATE(priv_id); /**< Key ID for opaque keys */
#endif /* MBEDTLS_PSA_CRYPTO_C */
+ /* The following fields are meant for storing the public key in raw format
+ * which is handy for:
+ * - easily importing it into the PSA context
+ * - reducing the ECP module dependencies in the PK one.
+ *
+ * When MBEDTLS_PK_USE_PSA_EC_DATA is enabled:
+ * - the pk_ctx above is not used anymore for storing the public key
+ * inside the ecp_keypair structure (only the private part, but also this
+ * one is going to change in the future)
+ * - the following fields are used for all public key operations: signature
+ * verify, key pair check and key write.
+ * Of course, when MBEDTLS_PK_USE_PSA_EC_DATA is not enabled, the legacy
+ * ecp_keypair structure is used for storing the public key and perform
+ * all the operations.
+ *
+ * Note: This new public key storing solution only works for EC keys, not
+ * other ones. The latters is still use pk_ctx to store their own
+ * context.
+ */
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+ uint8_t MBEDTLS_PRIVATE(pub_raw)[MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN]; /**< Raw public key */
+ size_t MBEDTLS_PRIVATE(pub_raw_len); /**< Valid bytes in "pub_raw" */
+ psa_ecc_family_t MBEDTLS_PRIVATE(ec_family); /**< EC family of pk */
+ size_t MBEDTLS_PRIVATE(ec_bits); /**< Curve's bits of pk */
+#endif /* MBEDTLS_PK_USE_PSA_EC_PUB_KEY */
} mbedtls_pk_context;
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)