If you use base64encoded strings as cookie names, make sure you remove '=' characters. At least Internet Explorer refuses cookie names containing '=' characters or urlencoded cookie names containing %xx character replacements. Use the function below to turn base64 encoded strings to bare alphabets (get rid of / and + characters as well)
<?php
function base64clean($base64string)
{
$base64string = str_replace(array('=','+','/'),'',$base64string);
return $base64string;
}
?>