Sop\JWX\JWE\KeyAlgorithm\RSAESKeyAlgorithm

Complexity

Total Complexity

19

Size/Duplication

Total Lines	178
Duplicated Lines	0 %

Test Coverage

Coverage

100%

Importance

Changes

0

11 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	5	1
A	fromPrivateKey()	0	3	1
A	_getLastOpenSSLError()	0	7	2
A	hasPrivateKey()	0	3	1
A	_decryptKey()	0	17	3
A	fromPublicKey()	0	3	1
A	_encryptKey()	0	17	3
A	privateKey()	0	6	2
A	publicKey()	0	3	1
A	headerParameters()	0	4	1
A	fromJWK()	0	11	3

<?php

declare(strict_types = 1);

namespace Sop\JWX\JWE\KeyAlgorithm;

use Sop\JWX\JWA\JWA;
use Sop\JWX\JWE\KeyAlgorithm\Feature\RandomCEK;
use Sop\JWX\JWE\KeyManagementAlgorithm;
use Sop\JWX\JWK\JWK;
use Sop\JWX\JWK\RSA\RSAPrivateKeyJWK;
use Sop\JWX\JWK\RSA\RSAPublicKeyJWK;
use Sop\JWX\JWT\Header\Header;
use Sop\JWX\JWT\Parameter\AlgorithmParameter;

/**
 * Base class for algorithms implementing RSA based key encryption.
 *
 * @see https://tools.ietf.org/html/rfc7518#section-4.2
 * @see https://tools.ietf.org/html/rfc7518#section-4.3
 */
abstract class RSAESKeyAlgorithm extends KeyManagementAlgorithm
{
    use RandomCEK;

    /**
     * Mapping from algorithm name to class name.
     *
     * @internal
     *
     * @var array
     */
    public const MAP_ALGO_TO_CLASS = [
        JWA::ALGO_RSA1_5 => RSAESPKCS1Algorithm::class,
        JWA::ALGO_RSA_OAEP => RSAESOAEPAlgorithm::class,
    ];

    /**
     * Public key.
     *
     * @var RSAPublicKeyJWK
     */
    protected $_publicKey;

    /**
     * Private key.
     *
     * @var null|RSAPrivateKeyJWK
     */
    protected $_privateKey;

    /**
     * Constructor.
     *
     * Use `fromPublicKey` or `fromPrivateKey` instead!
     *
     * @param RSAPublicKeyJWK  $pub_key  RSA public key
     * @param RSAPrivateKeyJWK $priv_key Optional RSA private key
     */
    protected function __construct(RSAPublicKeyJWK $pub_key,
        ?RSAPrivateKeyJWK $priv_key = null)
    {
        $this->_publicKey = $pub_key;
        $this->_privateKey = $priv_key;
    }

    /**
     * Initialize from JWK.
     *
     * @throws \UnexpectedValueException
     *
     * @return self
     */
    public static function fromJWK(JWK $jwk, Header $header): KeyManagementAlgorithm
    {
        $alg = JWA::deriveAlgorithmName($header, $jwk);
        if (!array_key_exists($alg, self::MAP_ALGO_TO_CLASS)) {
            throw new \UnexpectedValueException("Unsupported algorithm '{$alg}'.");
        }
        $cls = self::MAP_ALGO_TO_CLASS[$alg];
        if ($jwk->has(...RSAPrivateKeyJWK::MANAGED_PARAMS)) {
            return $cls::fromPrivateKey(RSAPrivateKeyJWK::fromJWK($jwk));
        }
        return $cls::fromPublicKey(RSAPublicKeyJWK::fromJWK($jwk));
    }

    /**
     * Initialize from a public key.
     */
    public static function fromPublicKey(RSAPublicKeyJWK $jwk): self
    {
        return new static($jwk);
    }

    /**
     * Initialize from a private key.
     */
    public static function fromPrivateKey(RSAPrivateKeyJWK $jwk): self
    {
        return new static($jwk->publicKey(), $jwk);
    }

    /**
     * Get the public key.
     */
    public function publicKey(): RSAPublicKeyJWK
    {
        return $this->_publicKey;
    }

    /**
     * Check whether the private key is present.
     */
    public function hasPrivateKey(): bool
    {
        return isset($this->_privateKey);
    }

    /**
     * Get the private key.
     *
     * @throws \LogicException
     */
    public function privateKey(): RSAPrivateKeyJWK
    {
        if (!$this->hasPrivateKey()) {
            throw new \LogicException('Private key not set.');
        }
        return $this->_privateKey;
    }

    /**
     * {@inheritdoc}
     */
    public function headerParameters(): array
    {
        return array_merge(parent::headerParameters(),
            [AlgorithmParameter::fromAlgorithm($this)]);
    }

    /**
     * Get the padding scheme.
     */
    abstract protected function _paddingScheme(): int;

    /**
     * {@inheritdoc}
     */
    protected function _encryptKey(string $key, Header &$header): string
    {
        $pubkey = openssl_pkey_get_public(
            $this->publicKey()->toPEM()->string());
        if (false === $pubkey) {
            throw new \RuntimeException(
                'openssl_pkey_get_public() failed: ' .
                     $this->_getLastOpenSSLError());
        }
        $result = openssl_public_encrypt($key, $crypted, $pubkey,
            $this->_paddingScheme());
        if (!$result) {
            throw new \RuntimeException(
                'openssl_public_encrypt() failed: ' .
                     $this->_getLastOpenSSLError());
        }
        return $crypted;
    }

    /**
     * {@inheritdoc}
     */
    protected function _decryptKey(string $ciphertext, Header $header): string
    {
        $privkey = openssl_pkey_get_private(
            $this->privateKey()->toPEM()->string());
        if (false === $privkey) {
            throw new \RuntimeException(
                'openssl_pkey_get_private() failed: ' .
                     $this->_getLastOpenSSLError());
        }
        $result = openssl_private_decrypt($ciphertext, $cek, $privkey,
            $this->_paddingScheme());
        if (!$result) {
            throw new \RuntimeException(
                'openssl_private_decrypt() failed: ' .
                     $this->_getLastOpenSSLError());
        }
        return $cek;
    }

    /**
     * Get last OpenSSL error message.
     */
    protected function _getLastOpenSSLError(): ?string
    {
        $msg = null;
        while (false !== ($err = openssl_error_string())) {
            $msg = $err;
        }
        return $msg;
    }
}