Dépôt pour Privatebin implémentation Chapril. https://paste.chapril.org/
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<?php
/**
* PrivateBin
*
* a zero-knowledge paste bin
*
* @link https://github.com/PrivateBin/PrivateBin
* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
* @license https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
* @version 1.3.4
*/
namespace PrivateBin;
/**
* FormatV2
*
* Provides validation function for version 2 format of pastes & comments.
*/
class FormatV2
{
/**
* version 2 format validator
*
* Checks if the given array is a proper version 2 formatted, encrypted message.
*
* @access public
* @static
* @param array $message
* @param bool $isComment
* @return bool
*/
public static function isValid($message, $isComment = false)
{
$required_keys = array('adata', 'v', 'ct');
if ($isComment) {
$required_keys[] = 'pasteid';
$required_keys[] = 'parentid';
} else {
$required_keys[] = 'meta';
}
// Make sure no additionnal keys were added.
if (count(array_keys($message)) != count($required_keys)) {
return false;
}
// Make sure required fields are present.
foreach ($required_keys as $k) {
if (!array_key_exists($k, $message)) {
return false;
}
}
$cipherParams = $isComment ? $message['adata'] : $message['adata'][0];
// Make sure some fields are base64 data:
// - initialization vector
if (!base64_decode($cipherParams[0], true)) {
return false;
}
// - salt
if (!base64_decode($cipherParams[1], true)) {
return false;
}
// - cipher text
if (!($ct = base64_decode($message['ct'], true))) {
return false;
}
// Make sure some fields have a reasonable size:
// - initialization vector
if (strlen($cipherParams[0]) > 24) {
return false;
}
// - salt
if (strlen($cipherParams[1]) > 14) {
return false;
}
// Make sure some fields contain no unsupported values:
// - version
if (!(is_int($message['v']) || is_float($message['v'])) || (float) $message['v'] < 2) {
return false;
}
// - iterations, refuse less then 10000 iterations (minimum NIST recommendation)
if (!is_int($cipherParams[2]) || $cipherParams[2] <= 10000) {
return false;
}
// - key size
if (!in_array($cipherParams[3], array(128, 192, 256), true)) {
return false;
}
// - tag size
if (!in_array($cipherParams[4], array(64, 96, 128), true)) {
return false;
}
// - algorithm, must be AES
if ($cipherParams[5] !== 'aes') {
return false;
}
// - mode
if (!in_array($cipherParams[6], array('ctr', 'cbc', 'gcm'), true)) {
return false;
}
// - compression
if (!in_array($cipherParams[7], array('zlib', 'none'), true)) {
return false;
}
// Reject data if entropy is too low
if (strlen($ct) > strlen(gzdeflate($ct))) {
return false;
}
// require only the key 'expire' in the metadata of pastes
if (!$isComment && (
count($message['meta']) === 0 ||
!array_key_exists('expire', $message['meta']) ||
count($message['meta']) > 1
)) {
return false;
}
return true;
}
}