Cookie.write = function (key, value, duration) {
    value=encrypt(value);
    Cookie.remove(key);
    var d = new Date();
    if (duration <= 0)
        duration = 1;
    d.setTime(d.getTime() + 1000 * 60 * 60 * 24 * duration);
    document.cookie = key + "=" + encodeURI(value) + "; expires=" + d.toGMTString() + ";path=/";
};

function encrypt(word)
{
    var key = CryptoJS.enc.Utf8.parse("010216a654976158");
    var iv  = CryptoJS.enc.Utf8.parse("010216a654976158");
    var src = CryptoJS.enc.Utf8.parse(word);
    var encrypted = CryptoJS.AES.encrypt(src, key, { iv:     iv,mode:CryptoJS.mode.CBC,padding:CryptoJS.pad.ZeroPadding});
    return encrypted.toString();
}

function decrypt(word)
{
    var key = CryptoJS.enc.Utf8.parse("010216a654976158");
    var iv  = CryptoJS.enc.Utf8.parse("010216a654976158");
    var decrypt = CryptoJS.AES.decrypt(word, key, { iv:      iv,mode:CryptoJS.mode.CBC,padding:CryptoJS.pad.ZeroPadding});
    return CryptoJS.enc.Utf8.stringify(decrypt).toString();
}

$uidE = $_COOKIE["uid"];
$decode = base64_decode($uidE);
$pk ="010216a654976158";
$iv ="010216a654976158";
$value = '4';

$encrypted = ( mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $pk, $value, MCRYPT_MODE_CBC,$iv) );

$uid = (mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $pk, $decode, MCRYPT_MODE_CBC,$iv));

echo base64_encode($encrypted);