openpgp-php/lib/OpenPgP/S2K.php
2020-06-18 22:03:56 +10:00

116 lines
2.2 KiB
PHP

<?php
namespace Leenooks\OpenPGP;
use Leenooks\OpenPGP;
class S2K
{
public $type, $hash_algorithm, $salt, $count;
function __construct($salt='BADSALT',$hash_algorithm=10,$count=65536,$type=3)
{
$this->type = $type;
$this->hash_algorithm = $hash_algorithm;
$this->salt = $salt;
$this->count = $count;
}
static function parse(&$input)
{
$s2k = new self;
switch($s2k->type = ord($input[0])) {
case 0:
$s2k->hash_algorithm = ord($input[1]);
$input = substr($input,2);
break;
case 1:
$s2k->hash_algorithm = ord($input[1]);
$s2k->salt = substr($input,2,8);
$input = substr($input,10);
break;
case 3:
$s2k->hash_algorithm = ord($input[1]);
$s2k->salt = substr($input,2,8);
$s2k->count = OpenPGP::decode_s2k_count(ord($input[10]));
$input = substr($input,11);
break;
}
return $s2k;
}
function to_bytes()
{
$bytes = chr($this->type);
switch($this->type) {
case 0:
$bytes .= chr($this->hash_algorithm);
break;
case 1:
if (strlen($this->salt) != 8)
throw new Exception('Invalid salt length');
$bytes .= chr($this->hash_algorithm);
$bytes .= $this->salt;
break;
case 3:
if (strlen($this->salt) != 8)
throw new Exception('Invalid salt length');
$bytes .= chr($this->hash_algorithm);
$bytes .= $this->salt;
$bytes .= chr(OpenPGP::encode_s2k_count($this->count));
break;
}
return $bytes;
}
function raw_hash($s)
{
return hash(strtolower(SignaturePacket::$hash_algorithms[$this->hash_algorithm]),$s,true);
}
function sized_hash($s,$size)
{
$hash = $this->raw_hash($s);
while(strlen($hash) < $size) {
$s = "\0".$s;
$hash .= $this->raw_hash($s);
}
return substr($hash,0,$size);
}
function iterate($s)
{
if (strlen($s) >= $this->count)
return $s;
$s = str_repeat($s,ceil($this->count/strlen($s)));
return substr($s,0,$this->count);
}
function make_key($pass,$size)
{
switch($this->type) {
case 0:
return $this->sized_hash($pass, $size);
case 1:
return $this->sized_hash($this->salt . $pass, $size);
case 3:
return $this->sized_hash($this->iterate($this->salt . $pass), $size);
}
}
}