diff --git a/library/sha512.c b/library/sha512.c
index 5537e8d..c13e0d9 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -242,7 +242,7 @@
     size_t fill;
     unsigned int left;
 
-    if( ilen <= 0 )
+    if( ilen == 0 )
         return;
 
     left = (unsigned int) (ctx->total[0] & 0x7F);