diff --git a/include/psa/crypto_platform.h b/include/psa/crypto_platform.h
index 77c0e5b..bd3dc10 100644
--- a/include/psa/crypto_platform.h
+++ b/include/psa/crypto_platform.h
@@ -74,27 +74,6 @@
 typedef int32_t psa_key_owner_id_t;
 #endif
 
-typedef struct
-{
-    uint32_t key_id;
-    psa_key_owner_id_t owner;
-} psa_key_file_id_t;
-#define PSA_KEY_FILE_GET_KEY_ID( file_id ) ( ( file_id ).key_id )
-
-/* Since crypto.h is used as part of the PSA Cryptography API specification,
- * it must use standard types for things like the argument of psa_open_key().
- * If it wasn't for that constraint, psa_open_key() would take a
- * `psa_key_file_id_t` argument. As a workaround, make `psa_key_id_t` an
- * alias for `psa_key_file_id_t` when building for a multi-client service. */
-typedef psa_key_file_id_t psa_key_id_t;
-#define PSA_KEY_ID_INIT {0, 0}
-
-#else /* !MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER */
-
-/* By default, a key file identifier is just the application key identifier. */
-typedef psa_app_key_id_t psa_key_file_id_t;
-#define PSA_KEY_FILE_GET_KEY_ID( id ) ( id )
-
-#endif /* !MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER */
+#endif /* MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER */
 
 #endif /* PSA_CRYPTO_PLATFORM_H */
diff --git a/include/psa/crypto_types.h b/include/psa/crypto_types.h
index 17718eb..f8811ad 100644
--- a/include/psa/crypto_types.h
+++ b/include/psa/crypto_types.h
@@ -33,6 +33,8 @@
 #ifndef PSA_CRYPTO_TYPES_H
 #define PSA_CRYPTO_TYPES_H
 
+#include "crypto_platform.h"
+
 #include <stdint.h>
 
 /** \defgroup error Error codes
@@ -229,12 +231,32 @@
 /* Implementation-specific quirk: The Mbed Crypto library can be built as
  * part of a multi-client service that exposes the PSA Crypto API in each
  * client and encodes the client identity in the key id argument of functions
- * such as psa_open_key(). In this build configuration, we define
- * psa_key_id_t in crypto_platform.h instead of here. */
+ * such as psa_open_key(). */
 #if !defined(MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER)
 typedef uint32_t psa_key_id_t;
+typedef psa_key_id_t psa_key_file_id_t;
+
 #define PSA_KEY_ID_INIT 0
-#endif
+#define PSA_KEY_FILE_GET_KEY_ID( id ) ( id )
+
+#else /* MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER */
+typedef struct
+{
+    uint32_t key_id;
+    psa_key_owner_id_t owner;
+} psa_key_file_id_t;
+
+/* Since crypto.h is used as part of the PSA Cryptography API specification,
+ * it must use standard types for things like the argument of psa_open_key().
+ * If it wasn't for that constraint, psa_open_key() would take a
+ * `psa_key_file_id_t` argument. As a workaround, make `psa_key_id_t` an
+ * alias for `psa_key_file_id_t` when building for a multi-client service. */
+typedef psa_key_file_id_t psa_key_id_t;
+
+#define PSA_KEY_ID_INIT {0, 0}
+#define PSA_KEY_FILE_GET_KEY_ID( file_id ) ( ( file_id ).key_id )
+
+#endif /* !MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER */
 
 /**@}*/