| protected static checksum ( string $cyphertext, string $iv, string $key, string $cipher = 'rijndael-128', string $mode = 'cbc', string $algo = 'sha256' ) : string | ||
| $cyphertext | string | Cyphertext that needs a checksum. |
| $iv | string | Initialization vector. |
| $key | string | HMAC key |
| $cipher | string | Cipher string |
| $mode | string | Cipher mode string |
| $algo | string | Hashing algorithm to use for internal operations |
| return | string | |
protected static function checksum($cyphertext, $iv, $key, $cipher = 'rijndael-128', $mode = 'cbc', $algo = 'sha256')
{
// Prevent potentially large string concat by hmac-ing the cyphertext
// by itself...
$sum = \hash_hmac($algo, $cyphertext, $key, true);
// ... then hash other elements with previous hmac and return
return \hash_hmac($algo, $sum . $iv . $mode . $cipher, $key, true);
}