diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index fb97b69..b40be07 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3449,22 +3449,21 @@
         goto exit;
     }
 
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
     /* Try any of the available accelerators first */
-    status = psa_driver_wrapper_sign_hash( slot,
-                                           alg,
-                                           hash,
-                                           hash_length,
-                                           signature,
-                                           signature_size,
-                                           signature_length );
+    status = psa_driver_wrapper_sign_hash(
+        &attributes, slot->key.data, slot->key.bytes,
+        alg, hash, hash_length,
+        signature, signature_size, signature_length );
+
     if( status != PSA_ERROR_NOT_SUPPORTED ||
         psa_key_lifetime_is_external( slot->attr.lifetime ) )
         goto exit;
 
     /* If the operation was not supported by any accelerator, try fallback. */
-    psa_key_attributes_t attributes = {
-      .core = slot->attr
-    };
     status = psa_sign_hash_internal(
         &attributes, slot->key.data, slot->key.bytes,
         alg, hash, hash_length,
@@ -3575,20 +3574,20 @@
     if( status != PSA_SUCCESS )
         return( status );
 
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
     /* Try any of the available accelerators first */
-    status = psa_driver_wrapper_verify_hash( slot,
-                                             alg,
-                                             hash,
-                                             hash_length,
-                                             signature,
-                                             signature_length );
+    status = psa_driver_wrapper_verify_hash(
+        &attributes, slot->key.data, slot->key.bytes,
+        alg, hash, hash_length,
+        signature, signature_length );
+
     if( status != PSA_ERROR_NOT_SUPPORTED ||
         psa_key_lifetime_is_external( slot->attr.lifetime ) )
         goto exit;
 
-    psa_key_attributes_t attributes = {
-      .core = slot->attr
-    };
     status = psa_verify_hash_internal(
         &attributes, slot->key.data, slot->key.bytes,
         alg, hash, hash_length,
diff --git a/library/psa_crypto_driver_wrappers.c b/library/psa_crypto_driver_wrappers.c
index 3cb7557..7597080 100644
--- a/library/psa_crypto_driver_wrappers.c
+++ b/library/psa_crypto_driver_wrappers.c
@@ -57,21 +57,21 @@
 #endif
 
 /* Start delegation functions */
-psa_status_t psa_driver_wrapper_sign_hash( psa_key_slot_t *slot,
-                                           psa_algorithm_t alg,
-                                           const uint8_t *hash,
-                                           size_t hash_length,
-                                           uint8_t *signature,
-                                           size_t signature_size,
-                                           size_t *signature_length )
+psa_status_t psa_driver_wrapper_sign_hash(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
+    uint8_t *signature, size_t signature_size, size_t *signature_length )
 {
+    (void)key_buffer_size;
+
 #if defined(PSA_CRYPTO_DRIVER_PRESENT)
     /* Try dynamically-registered SE interface first */
 #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
     const psa_drv_se_t *drv;
     psa_drv_se_context_t *drv_context;
 
-    if( psa_get_se_driver( slot->attr.lifetime, &drv, &drv_context ) )
+    if( psa_get_se_driver( attributes->core.lifetime, &drv, &drv_context ) )
     {
         if( drv->asymmetric == NULL ||
             drv->asymmetric->p_sign == NULL )
@@ -79,22 +79,18 @@
             /* Key is defined in SE, but we have no way to exercise it */
             return( PSA_ERROR_NOT_SUPPORTED );
         }
-        return( drv->asymmetric->p_sign( drv_context,
-                                         psa_key_slot_get_slot_number( slot ),
-                                         alg,
-                                         hash, hash_length,
-                                         signature, signature_size,
-                                         signature_length ) );
+        return( drv->asymmetric->p_sign(
+                    drv_context, *( (psa_key_slot_number_t *)key_buffer ),
+                    alg, hash, hash_length,
+                    signature, signature_size, signature_length ) );
     }
 #endif /* PSA_CRYPTO_SE_C */
 
     /* Then try accelerator API */
 #if defined(PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT)
     psa_status_t status = PSA_ERROR_INVALID_ARGUMENT;
-    psa_key_location_t location = PSA_KEY_LIFETIME_GET_LOCATION(slot->attr.lifetime);
-    psa_key_attributes_t attributes = {
-      .core = slot->attr
-    };
+    psa_key_location_t location =
+        PSA_KEY_LIFETIME_GET_LOCATION( attributes->core.lifetime );
 
     switch( location )
     {
@@ -102,9 +98,9 @@
             /* Key is stored in the slot in export representation, so
              * cycle through all known transparent accelerators */
 #if defined(PSA_CRYPTO_DRIVER_TEST)
-            status = test_transparent_signature_sign_hash( &attributes,
-                                                           slot->key.data,
-                                                           slot->key.bytes,
+            status = test_transparent_signature_sign_hash( attributes,
+                                                           key_buffer,
+                                                           key_buffer_size,
                                                            alg,
                                                            hash,
                                                            hash_length,
@@ -120,9 +116,9 @@
         /* Add cases for opaque driver here */
 #if defined(PSA_CRYPTO_DRIVER_TEST)
         case PSA_CRYPTO_TEST_DRIVER_LIFETIME:
-            return( test_opaque_signature_sign_hash( &attributes,
-                                                     slot->key.data,
-                                                     slot->key.bytes,
+            return( test_opaque_signature_sign_hash( attributes,
+                                                     key_buffer,
+                                                     key_buffer_size,
                                                      alg,
                                                      hash,
                                                      hash_length,
@@ -138,7 +134,8 @@
     return( PSA_ERROR_NOT_SUPPORTED );
 #endif /* PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT */
 #else /* PSA_CRYPTO_DRIVER_PRESENT */
-    (void)slot;
+    (void)attributes;
+    (void)key_buffer;
     (void)alg;
     (void)hash;
     (void)hash_length;
@@ -150,20 +147,21 @@
 #endif /* PSA_CRYPTO_DRIVER_PRESENT */
 }
 
-psa_status_t psa_driver_wrapper_verify_hash( psa_key_slot_t *slot,
-                                             psa_algorithm_t alg,
-                                             const uint8_t *hash,
-                                             size_t hash_length,
-                                             const uint8_t *signature,
-                                             size_t signature_length )
+psa_status_t psa_driver_wrapper_verify_hash(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
+    const uint8_t *signature, size_t signature_length )
 {
+    (void)key_buffer_size;
+
 #if defined(PSA_CRYPTO_DRIVER_PRESENT)
     /* Try dynamically-registered SE interface first */
 #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
     const psa_drv_se_t *drv;
     psa_drv_se_context_t *drv_context;
 
-    if( psa_get_se_driver( slot->attr.lifetime, &drv, &drv_context ) )
+    if( psa_get_se_driver( attributes->core.lifetime, &drv, &drv_context ) )
     {
         if( drv->asymmetric == NULL ||
             drv->asymmetric->p_verify == NULL )
@@ -171,21 +169,18 @@
             /* Key is defined in SE, but we have no way to exercise it */
             return( PSA_ERROR_NOT_SUPPORTED );
         }
-        return( drv->asymmetric->p_verify( drv_context,
-                                           psa_key_slot_get_slot_number( slot ),
-                                           alg,
-                                           hash, hash_length,
-                                           signature, signature_length ) );
+        return( drv->asymmetric->p_verify(
+                    drv_context, *( (psa_key_slot_number_t *)key_buffer ),
+                    alg, hash, hash_length,
+                    signature, signature_length ) );
     }
 #endif /* PSA_CRYPTO_SE_C */
 
     /* Then try accelerator API */
 #if defined(PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT)
     psa_status_t status = PSA_ERROR_INVALID_ARGUMENT;
-    psa_key_location_t location = PSA_KEY_LIFETIME_GET_LOCATION(slot->attr.lifetime);
-    psa_key_attributes_t attributes = {
-      .core = slot->attr
-    };
+    psa_key_location_t location =
+        PSA_KEY_LIFETIME_GET_LOCATION( attributes->core.lifetime );
 
     switch( location )
     {
@@ -193,9 +188,9 @@
             /* Key is stored in the slot in export representation, so
              * cycle through all known transparent accelerators */
 #if defined(PSA_CRYPTO_DRIVER_TEST)
-            status = test_transparent_signature_verify_hash( &attributes,
-                                                             slot->key.data,
-                                                             slot->key.bytes,
+            status = test_transparent_signature_verify_hash( attributes,
+                                                             key_buffer,
+                                                             key_buffer_size,
                                                              alg,
                                                              hash,
                                                              hash_length,
@@ -210,9 +205,9 @@
         /* Add cases for opaque driver here */
 #if defined(PSA_CRYPTO_DRIVER_TEST)
         case PSA_CRYPTO_TEST_DRIVER_LIFETIME:
-            return( test_opaque_signature_verify_hash( &attributes,
-                                                       slot->key.data,
-                                                       slot->key.bytes,
+            return( test_opaque_signature_verify_hash( attributes,
+                                                       key_buffer,
+                                                       key_buffer_size,
                                                        alg,
                                                        hash,
                                                        hash_length,
@@ -227,7 +222,8 @@
     return( PSA_ERROR_NOT_SUPPORTED );
 #endif /* PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT */
 #else /* PSA_CRYPTO_DRIVER_PRESENT */
-    (void)slot;
+    (void)attributes;
+    (void)key_buffer;
     (void)alg;
     (void)hash;
     (void)hash_length;
diff --git a/library/psa_crypto_driver_wrappers.h b/library/psa_crypto_driver_wrappers.h
index ad16cdd..22d22d6 100644
--- a/library/psa_crypto_driver_wrappers.h
+++ b/library/psa_crypto_driver_wrappers.h
@@ -28,20 +28,17 @@
 /*
  * Signature functions
  */
-psa_status_t psa_driver_wrapper_sign_hash( psa_key_slot_t *slot,
-                                           psa_algorithm_t alg,
-                                           const uint8_t *hash,
-                                           size_t hash_length,
-                                           uint8_t *signature,
-                                           size_t signature_size,
-                                           size_t *signature_length );
+psa_status_t psa_driver_wrapper_sign_hash(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
+    uint8_t *signature, size_t signature_size, size_t *signature_length );
 
-psa_status_t psa_driver_wrapper_verify_hash( psa_key_slot_t *slot,
-                                             psa_algorithm_t alg,
-                                             const uint8_t *hash,
-                                             size_t hash_length,
-                                             const uint8_t *signature,
-                                             size_t signature_length );
+psa_status_t psa_driver_wrapper_verify_hash(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
+    const uint8_t *signature, size_t signature_length );
 
 /*
  * Key handling functions