그누보드 캐시 암호화, 복호화 하는 방법

/lib/Cache/FileCache.class.php

/**
* Encodes some data to a string so it can be written to disk
*
* @param mixed $data
* @param int $ttl
* @return string
*/
public function encode($data, $ttl)
{
$expire = null;
if ($ttl !== null) {
$expire = time() + $ttl;
}
return base64_encode(serialize(array($data, $expire)));
}

/**
* Decodes a string encoded by {@see encode()}
*
* Must returns a tuple (data, expire). Expire
* can be null to signal no expiration.
*
* @param string $data
* @return array (data, expire)
*/
public function decode($data)
{
return unserialize(base64_decode($data));
}