New function mbedtls_ecp_keypair_get_group_id
Add a simple function to get the group id from a key object.
This information is available via mbedtls_ecp_export, but that function
consumes a lot of memory, which is a waste if all you need is to identify
the curve.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 7f5e880..a29a6f7 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -1323,6 +1323,18 @@
const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
+/** \brief Query the group that a key pair belongs to.
+ *
+ * \param key The key pair to query.
+ *
+ * \return The group ID for the group registered in the key pair
+ * object.
+ * This is \c MBEDTLS_ECP_DP_NONE if no group has been set
+ * in the key pair object.
+ */
+mbedtls_ecp_group_id mbedtls_ecp_keypair_get_group_id(
+ const mbedtls_ecp_keypair *key);
+
/**
* \brief This function exports generic key-pair parameters.
*