<?php
/**
* Holds the key for @{class:PhutilOpaqueEnvelope} in a logically distant
* location so it will never appear in stack traces, etc. You should never need
* to use this class directly. See @{class:PhutilOpaqueEnvelope} for
* information about opaque envelopes.
*
* @task internal Internals
*/
final class PhutilOpaqueEnvelopeKey extends Phobject {
private static $key;
/* -( Internals )---------------------------------------------------------- */
/**
* @task internal
*/
private function __construct() {
// <private>
}
/**
* @task internal
*/
public static function getKey() {
if (self::$key === null) {
// NOTE: We're using a weak random source because cryptographic levels
// of security aren't terribly important here and it allows us to use
// envelopes on systems which don't have a strong random source. Notably,
// this lets us make it to the readability check for `/dev/urandom` in
// Phabricator on systems where we can't read it.
self::$key = '';
for ($ii = 0; $ii < 8; $ii++) {
self::$key .= md5(mt_rand(), $raw_output = true);
}
}
return self::$key;
}
}