diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index b8abfd0..d3ac4ce 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -2683,6 +2683,37 @@
     return PSA_SUCCESS;
 }
 
+/**
+ * \brief                       Fill the unused part of the output buffer(the
+ *                              whole buffer on error, the trailing part on
+ *                              success) with something that isn't a valid
+ *                              signature (barring an attack on the signature
+ *                              and deliberately-crafted input), in case the
+ *                              caller doesn't check the return status properly.
+ *
+ * \param output_buffer         pointer to buffer to wipe. May not be NULL
+ *                              unless /p output_buffer_size is zero.
+ * \param status                status of function called to generate
+ *                              output_buffer originally
+ * \param output_buffer_size    Size of output buffer. If zero, /p output_buffer
+ *                              could be NULL
+ * \param output_buffer_length  Length of data written to output_buffer, must be
+ *                              less than /p output_buffer_size
+ */
+static void psa_wipe_output_buffer(uint8_t *output_buffer, psa_status_t status,
+                                   size_t output_buffer_size, size_t output_buffer_length)
+{
+    if (status == PSA_SUCCESS) {
+        memset(output_buffer + output_buffer_length, '!',
+               output_buffer_size - output_buffer_length);
+    } else if (output_buffer_size > 0) {
+        memset(output_buffer, '!', output_buffer_size);
+    }
+    /* If output_buffer_size is 0 then we have nothing to do. We must
+     * not call memset because output_buffer may be NULL in this
+     * case.*/
+}
+
 static psa_status_t psa_sign_internal(mbedtls_svc_key_id_t key,
                                       int input_is_message,
                                       psa_algorithm_t alg,
@@ -2745,18 +2776,8 @@
 
 
 exit:
-    /* Fill the unused part of the output buffer (the whole buffer on error,
-     * the trailing part on success) with something that isn't a valid signature
-     * (barring an attack on the signature and deliberately-crafted input),
-     * in case the caller doesn't check the return status properly. */
-    if (status == PSA_SUCCESS) {
-        memset(signature + *signature_length, '!',
-               signature_size - *signature_length);
-    } else {
-        memset(signature, '!', signature_size);
-    }
-    /* If signature_size is 0 then we have nothing to do. We must not call
-     * memset because signature may be NULL in this case. */
+    psa_wipe_output_buffer(signature, status, signature_size,
+                           *signature_length);
 
     unlock_status = psa_unlock_key_slot(slot);
 
@@ -3268,19 +3289,8 @@
     operation->num_ops += psa_driver_wrapper_sign_hash_get_num_ops(operation);
 
     if (status != PSA_OPERATION_INCOMPLETE) {
-        /* Fill the unused part of the output buffer (the whole buffer on error,
-         * the trailing part on success) with something that isn't a valid
-         * signature (barring an attack on the signature and
-         * deliberately-crafted input), in case the caller doesn't check the
-         * return status properly.*/
-        if (status == PSA_SUCCESS) {
-            memset(signature + *signature_length, '!',
-                   signature_size - *signature_length);
-        } else if (signature_size > 0) {
-            memset(signature, '!', signature_size);
-        }
-        /* If signature_size is 0 then we have nothing to do. We must not
-         * call memset because signature may be NULL in this case.*/
+        psa_wipe_output_buffer(signature, status, signature_size,
+                               *signature_length);
 
         if (status != PSA_SUCCESS) {
             operation->error_occurred = 1;