diff --git a/phpseclib/Crypt/Base.php b/phpseclib/Crypt/Base.php
index aca2554d..d94d7517 100644
--- a/phpseclib/Crypt/Base.php
+++ b/phpseclib/Crypt/Base.php
@@ -2008,7 +2008,9 @@ class Crypt_Base
     function _increment_str(&$var)
     {
         if (function_exists('sodium_increment')) {
+            $var = strrev($var);
             sodium_increment($var);
+            $var = strrev($var);
             return;
         }