<?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\KeyManagement\KeyConverter;
use Base64Url\Base64Url;
use Jose\Component\Core\JWK;
use Jose\Component\Core\Util\BigInteger;
/**
* @internal
*/
class RSAKey
{
/**
* @var array
*/
private $values = [];
/**
* RSAKey constructor.
*/
private function __construct(array $data)
{
$this->loadJWK($data);
}
/**
* @return RSAKey
*/
public static function createFromKeyDetails(array $details): self
{
$values = ['kty' => 'RSA'];
$keys = [
'n' => 'n',
'e' => 'e',
'd' => 'd',
'p' => 'p',
'q' => 'q',
'dp' => 'dmp1',
'dq' => 'dmq1',
'qi' => 'iqmp',
];
foreach ($details as $key => $value) {
if (\in_array($key, $keys, true)) {
$value = Base64Url::encode($value);
$values[\array_search($key, $keys, true)] = $value;
}
}
return new self($values);
}
/**
* @return RSAKey
*/
public static function createFromPEM(string $pem): self
{
$res = \openssl_pkey_get_private($pem);
if (false === $res) {
$res = \openssl_pkey_get_public($pem);
}
if (false === $res) {
throw new \InvalidArgumentException('Unable to load the key.');
}
$details = \openssl_pkey_get_details($res);
\openssl_free_key($res);
if (!\array_key_exists('rsa', $details)) {
throw new \InvalidArgumentException('Unable to load the key.');
}
return self::createFromKeyDetails($details['rsa']);
}
/**
* @return RSAKey
*/
public static function createFromJWK(JWK $jwk): self
{
return new self($jwk->all());
}
public function isPublic(): bool
{
return !\array_key_exists('d', $this->values);
}
/**
* @param RSAKey $private
*
* @return RSAKey
*/
public static function toPublic(self $private): self
{
$data = $private->toArray();
$keys = ['p', 'd', 'q', 'dp', 'dq', 'qi'];
foreach ($keys as $key) {
if (\array_key_exists($key, $data)) {
unset($data[$key]);
}
}
return new self($data);
}
public function toArray(): array
{
return $this->values;
}
private function loadJWK(array $jwk)
{
if (!\array_key_exists('kty', $jwk)) {
throw new \InvalidArgumentException('The key parameter "kty" is missing.');
}
if ('RSA' !== $jwk['kty']) {
throw new \InvalidArgumentException('The JWK is not a RSA key.');
}
$this->values = $jwk;
}
public function toJwk(): JWK
{
return new JWK($this->values);
}
/**
* This method will try to add Chinese Remainder Theorem (CRT) parameters.
* With those primes, the decryption process is really fast.
*/
public function optimize()
{
if (\array_key_exists('d', $this->values)) {
$this->populateCRT();
}
}
/**
* This method adds Chinese Remainder Theorem (CRT) parameters if primes 'p' and 'q' are available.
*/
private function populateCRT()
{
if (!\array_key_exists('p', $this->values) && !\array_key_exists('q', $this->values)) {
$d = BigInteger::createFromBinaryString(Base64Url::decode($this->values['d']));
$e = BigInteger::createFromBinaryString(Base64Url::decode($this->values['e']));
$n = BigInteger::createFromBinaryString(Base64Url::decode($this->values['n']));
list($p, $q) = $this->findPrimeFactors($d, $e, $n);
$this->values['p'] = Base64Url::encode($p->toBytes());
$this->values['q'] = Base64Url::encode($q->toBytes());
}
if (\array_key_exists('dp', $this->values) && \array_key_exists('dq', $this->values) && \array_key_exists('qi', $this->values)) {
return;
}
$one = BigInteger::createFromDecimal(1);
$d = BigInteger::createFromBinaryString(Base64Url::decode($this->values['d']));
$p = BigInteger::createFromBinaryString(Base64Url::decode($this->values['p']));
$q = BigInteger::createFromBinaryString(Base64Url::decode($this->values['q']));
$this->values['dp'] = Base64Url::encode($d->mod($p->subtract($one))->toBytes());
$this->values['dq'] = Base64Url::encode($d->mod($q->subtract($one))->toBytes());
$this->values['qi'] = Base64Url::encode($q->modInverse($p)->toBytes());
}
/**
* @return BigInteger[]
*/
private function findPrimeFactors(BigInteger $d, BigInteger $e, BigInteger $n): array
{
$zero = BigInteger::createFromDecimal(0);
$one = BigInteger::createFromDecimal(1);
$two = BigInteger::createFromDecimal(2);
$k = $d->multiply($e)->subtract($one);
if ($k->isEven()) {
$r = $k;
$t = $zero;
do {
$r = $r->divide($two);
$t = $t->add($one);
} while ($r->isEven());
$found = false;
$y = null;
for ($i = 1; $i <= 100; ++$i) {
$g = BigInteger::random($n->subtract($one));
$y = $g->modPow($r, $n);
if ($y->equals($one) || $y->equals($n->subtract($one))) {
continue;
}
for ($j = $one; $j->lowerThan($t->subtract($one)); $j = $j->add($one)) {
$x = $y->modPow($two, $n);
if ($x->equals($one)) {
$found = true;
break;
}
if ($x->equals($n->subtract($one))) {
continue;
}
$y = $x;
}
$x = $y->modPow($two, $n);
if ($x->equals($one)) {
$found = true;
break;
}
}
if (true === $found) {
$p = $y->subtract($one)->gcd($n);
$q = $n->divide($p);
return [$p, $q];
}
}
throw new \InvalidArgumentException('Unable to find prime factors.');
}
}