diff --git a/library/rsa.c b/library/rsa.c
index 8ec7aab..f4ff237 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -809,7 +809,7 @@
          * (minus one, for the 00 byte) */
         for( i = 0; i < ilen - 3; i++ )
         {
-            pad_done |= ( p[i] == 0xFF );
+            pad_done |= ( p[i] != 0xFF );
             pad_count += ( pad_done == 0 );
         }