diff --git a/source/ak_belt_hash.c b/source/ak_belt_hash.c
index 5749e87d7a82b120f9d2ff93554c6ce9bdd44e48..a92d3e82fbd3fe90d612e2389438dcca6eeb1d35 100644
--- a/source/ak_belt_hash.c
+++ b/source/ak_belt_hash.c
@@ -134,7 +134,7 @@ static int ak_hash_context_belt_finalize(ak_pointer sctx,
 
     ak_hash_context_belt_update(sctx, in, (size /32)*32);
 
-    if (ssize || !size)
+    if ((size & 31) || !size)
     {
         memset(lastBlock, 0, 64); // Заполняем последний блок
         memcpy(lastBlock, din, ssize);