Use enum for slot state in PSA-based cipher context
diff --git a/include/mbedtls/cipher_internal.h b/include/mbedtls/cipher_internal.h
index f1f0e2b..cecad9a 100644
--- a/include/mbedtls/cipher_internal.h
+++ b/include/mbedtls/cipher_internal.h
@@ -119,14 +119,26 @@
} mbedtls_cipher_definition_t;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
+typedef enum
+{
+ MBEDTLS_CIPHER_PSA_KEY_UNSET = 0,
+ MBEDTLS_CIPHER_PSA_KEY_OWNED, /* Used for PSA-based cipher contexts
+ * which use raw key material internally
+ * imported into a freshly allocated key slot,
+ * and which hence need to destroy that key
+ * slot when they are no longer needed. */
+ MBEDTLS_CIPHER_PSA_KEY_NOT_OWNED, /* Used for PSA-based cipher contexts
+ * which use a key from a key slot
+ * provided by the user, and which hence
+ * should not be destroyed when the
+ * context is no longer needed. */
+} mbedtls_cipher_psa_key_ownership;
+
typedef struct
{
psa_algorithm_t alg;
psa_key_slot_t slot;
- unsigned char slot_state; /*!< 0: The slot is unset.
- * 1: The slot is set and we own it.
- * 2: The slot is set but we don't own it. */
-
+ mbedtls_cipher_psa_key_ownership slot_state;
} mbedtls_cipher_context_psa;
#endif /* MBEDTLS_USE_PSA_CRYPTO */