diff --git a/ChangeLog b/ChangeLog
index eb4ecf790..a28601f80 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,7 @@ $HeadURL$
     * themes/darkblue_orange/css/theme_right.css.php,
       themes/original/css/theme_right.css.php,
       libraries/database_interface.lib.php: Fix typos (bug #1597137).
+    * libraries/unzip.lib.php: Fix check for encrypted file (bug #1596304).
 
 2006-11-19 Marc Delisle  <lem9@users.sourceforge.net>
     * pmd_general.php, pmd_get_info.php, pmd/scripts/move.js,
diff --git a/libraries/unzip.lib.php b/libraries/unzip.lib.php
index df3264f49..1a0b5731a 100644
--- a/libraries/unzip.lib.php
+++ b/libraries/unzip.lib.php
@@ -278,7 +278,7 @@
                 // Retrieving local file header information
                 $aP = unpack('v1VN/v1GPF/v1CM/v1FT/v1FD/V1CRC/V1CS/V1UCS/v1FNL', $vZ);
                 // Check if data is encrypted
-                $bE = ($aP['GPF'] && 0x0001) ? TRUE : FALSE;
+                $bE = ($aP['GPF'] & 0x0001) ? TRUE : FALSE;
                 $nF = $aP['FNL'];
 
                 // Special case : value block after the compressed data