diff --git a/include/psa/crypto_compat.h b/include/psa/crypto_compat.h
index 4b607b6..fea2923 100644
--- a/include/psa/crypto_compat.h
+++ b/include/psa/crypto_compat.h
@@ -34,6 +34,40 @@
 extern "C" {
 #endif
 
+/*
+ * To support temporary both openless APIs and psa_open_key(), define
+ * psa_key_handle_t to be equal to mbedtls_svc_key_id_t. Do not mark the
+ * type and its utility macros and functions deprecated yet. This will be done
+ * in a subsequent phase.
+ */
+typedef mbedtls_svc_key_id_t psa_key_handle_t;
+
+#define PSA_KEY_HANDLE_INIT MBEDTLS_SVC_KEY_ID_INIT
+
+/** Compare two handles.
+ *
+ * \param handle1  First handle.
+ * \param handle2  Second handle.
+ *
+ * \return Non-zero if the two handles are equal, zero otherwise.
+ */
+static inline int psa_key_handle_equal( psa_key_handle_t handle1,
+                                        psa_key_handle_t handle2 )
+{
+    return( mbedtls_svc_key_id_equal( handle1, handle2 ) );
+}
+
+/** Check wether an handle is null.
+ *
+ * \param handle  Handle
+ *
+ * \return Non-zero if the handle is null, zero otherwise.
+ */
+static inline int psa_key_handle_is_null( psa_key_handle_t handle )
+{
+    return( mbedtls_svc_key_id_is_null( handle ) );
+}
+
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
 
 /*
@@ -223,6 +257,107 @@
 #define PSA_DH_GROUP_CUSTOM \
     MBEDTLS_DEPRECATED_CONSTANT( psa_dh_family_t, PSA_DH_FAMILY_CUSTOM )
 
+/** Open a handle to an existing persistent key.
+ *
+ * Open a handle to a persistent key. A key is persistent if it was created
+ * with a lifetime other than #PSA_KEY_LIFETIME_VOLATILE. A persistent key
+ * always has a nonzero key identifier, set with psa_set_key_id() when
+ * creating the key. Implementations may provide additional pre-provisioned
+ * keys that can be opened with psa_open_key(). Such keys have an application
+ * key identifier in the vendor range, as documented in the description of
+ * #psa_key_id_t.
+ *
+ * The application must eventually close the handle with psa_close_key() or
+ * psa_destroy_key() to release associated resources. If the application dies
+ * without calling one of these functions, the implementation should perform
+ * the equivalent of a call to psa_close_key().
+ *
+ * Some implementations permit an application to open the same key multiple
+ * times. If this is successful, each call to psa_open_key() will return a
+ * different key handle.
+ *
+ * \note This API is not part of the PSA Cryptography API Release 1.0.0
+ * specification. It was defined in the 1.0 Beta 3 version of the
+ * specification but was removed in the 1.0.0 released version. This API is
+ * kept for the time being to not break applications relying on it. It is not
+ * deprecated yet but will be in the near future.
+ *
+ * \note Applications that rely on opening a key multiple times will not be
+ * portable to implementations that only permit a single key handle to be
+ * opened. See also :ref:\`key-handles\`.
+ *
+ *
+ * \param key           The persistent identifier of the key.
+ * \param[out] handle   On success, a handle to the key.
+ *
+ * \retval #PSA_SUCCESS
+ *         Success. The application can now use the value of `*handle`
+ *         to access the key.
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ *         The implementation does not have sufficient resources to open the
+ *         key. This can be due to reaching an implementation limit on the
+ *         number of open keys, the number of open key handles, or available
+ *         memory.
+ * \retval #PSA_ERROR_DOES_NOT_EXIST
+ *         There is no persistent key with key identifier \p id.
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ *         \p id is not a valid persistent key identifier.
+ * \retval #PSA_ERROR_NOT_PERMITTED
+ *         The specified key exists, but the application does not have the
+ *         permission to access it. Note that this specification does not
+ *         define any way to create such a key, but it may be possible
+ *         through implementation-specific means.
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_CORRUPTION_DETECTED
+ * \retval #PSA_ERROR_STORAGE_FAILURE
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The library has not been previously initialized by psa_crypto_init().
+ *         It is implementation-dependent whether a failure to initialize
+ *         results in this error code.
+ */
+psa_status_t psa_open_key( mbedtls_svc_key_id_t key,
+                           psa_key_handle_t *handle );
+
+/** Close a key handle.
+ *
+ * If the handle designates a volatile key, this will destroy the key material
+ * and free all associated resources, just like psa_destroy_key().
+ *
+ * If this is the last open handle to a persistent key, then closing the handle
+ * will free all resources associated with the key in volatile memory. The key
+ * data in persistent storage is not affected and can be opened again later
+ * with a call to psa_open_key().
+ *
+ * Closing the key handle makes the handle invalid, and the key handle
+ * must not be used again by the application.
+ *
+ * \note This API is not part of the PSA Cryptography API Release 1.0.0
+ * specification. It was defined in the 1.0 Beta 3 version of the
+ * specification but was removed in the 1.0.0 released version. This API is
+ * kept for the time being to not break applications relying on it. It is not
+ * deprecated yet but will be in the near future.
+ *
+ * \note If the key handle was used to set up an active
+ * :ref:\`multipart operation <multipart-operations>\`, then closing the
+ * key handle can cause the multipart operation to fail. Applications should
+ * maintain the key handle until after the multipart operation has finished.
+ *
+ * \param handle        The key handle to close.
+ *                      If this is \c 0, do nothing and return \c PSA_SUCCESS.
+ *
+ * \retval #PSA_SUCCESS
+ *         \p handle was a valid handle or \c 0. It is now closed.
+ * \retval #PSA_ERROR_INVALID_HANDLE
+ *         \p handle is not a valid handle nor \c 0.
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_CORRUPTION_DETECTED
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The library has not been previously initialized by psa_crypto_init().
+ *         It is implementation-dependent whether a failure to initialize
+ *         results in this error code.
+ */
+psa_status_t psa_close_key(psa_key_handle_t handle);
+
 #ifdef __cplusplus
 }
 #endif