<?php
declare(strict_types=1);
/*
* The MIT License (MIT)
*
* Copyright (c) 2014-2018 Spomky-Labs
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
*/
namespace Jose\Component\Core\Util;
/**
* @internal
*/
class ECSignature
{
public static function toDER(string $signature, int $partLength): string
{
$signature = \unpack('H*', $signature)[1];
if (\mb_strlen($signature, '8bit') !== 2 * $partLength) {
throw new \InvalidArgumentException('Invalid length.');
}
$R = \mb_substr($signature, 0, $partLength, '8bit');
$S = \mb_substr($signature, $partLength, null, '8bit');
$R = self::preparePositiveInteger($R);
$Rl = \mb_strlen($R, '8bit') / 2;
$S = self::preparePositiveInteger($S);
$Sl = \mb_strlen($S, '8bit') / 2;
$der = \pack('H*',
'30'.($Rl + $Sl + 4 > 128 ? '81' : '').\dechex($Rl + $Sl + 4)
.'02'.\dechex($Rl).$R
.'02'.\dechex($Sl).$S
);
return $der;
}
public static function fromDER(string $der, int $partLength): string
{
$hex = \unpack('H*', $der)[1];
if ('30' !== \mb_substr($hex, 0, 2, '8bit')) { // SEQUENCE
throw new \RuntimeException();
}
if ('81' === \mb_substr($hex, 2, 2, '8bit')) { // LENGTH > 128
$hex = \mb_substr($hex, 6, null, '8bit');
} else {
$hex = \mb_substr($hex, 4, null, '8bit');
}
if ('02' !== \mb_substr($hex, 0, 2, '8bit')) { // INTEGER
throw new \RuntimeException();
}
$Rl = \hexdec(\mb_substr($hex, 2, 2, '8bit'));
$R = self::retrievePositiveInteger(\mb_substr($hex, 4, $Rl * 2, '8bit'));
$R = \str_pad($R, $partLength, '0', STR_PAD_LEFT);
$hex = \mb_substr($hex, 4 + $Rl * 2, null, '8bit');
if ('02' !== \mb_substr($hex, 0, 2, '8bit')) { // INTEGER
throw new \RuntimeException();
}
$Sl = \hexdec(\mb_substr($hex, 2, 2, '8bit'));
$S = self::retrievePositiveInteger(\mb_substr($hex, 4, $Sl * 2, '8bit'));
$S = \str_pad($S, $partLength, '0', STR_PAD_LEFT);
return \pack('H*', $R.$S);
}
private static function preparePositiveInteger(string $data): string
{
if (\mb_substr($data, 0, 2, '8bit') > '7f') {
return '00'.$data;
}
while ('00' === \mb_substr($data, 0, 2, '8bit') && \mb_substr($data, 2, 2, '8bit') <= '7f') {
$data = \mb_substr($data, 2, null, '8bit');
}
return $data;
}
private static function retrievePositiveInteger(string $data): string
{
while ('00' === \mb_substr($data, 0, 2, '8bit') && \mb_substr($data, 2, 2, '8bit') > '7f') {
$data = \mb_substr($data, 2, null, '8bit');
}
return $data;
}
}