Completed
Branch develop (8ddc4a)
by Florent
02:46
created

PBES2AESKW::wrapKey()   A

Complexity

Conditions 1
Paths 1

Size

Total Lines 18
Code Lines 12

Duplication

Lines 0
Ratio 0 %
Metric Value
dl 0
loc 18
rs 9.4285
cc 1
eloc 12
nc 1
nop 4
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<?php
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/*
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 * The MIT License (MIT)
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 *
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 * Copyright (c) 2014-2016 Spomky-Labs
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 *
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 * This software may be modified and distributed under the terms
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 * of the MIT license.  See the LICENSE file for details.
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 */
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namespace Jose\Algorithm\KeyEncryption;
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use Assert\Assertion;
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use Base64Url\Base64Url;
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use Jose\Object\JWKInterface;
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use Jose\Util\StringUtil;
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/**
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 * Class PBES2AESKW.
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 */
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abstract class PBES2AESKW implements KeyWrappingInterface
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{
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    /**
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     * @var int
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     */
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    private $salt_size;
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    /**
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     * @var int
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     */
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    private $nb_count;
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    /**
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     * @param int $salt_size
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     * @param int $nb_count
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     */
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    public function __construct($salt_size = 64, $nb_count = 4096)
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    {
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        $this->salt_size = $salt_size;
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        $this->nb_count = $nb_count;
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    }
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    /**
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     * {@inheritdoc}
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     */
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    public function wrapKey(JWKInterface $key, $cek, array $complete_headers, array &$additional_headers)
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    {
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        $this->checkKey($key);
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        $this->checkHeaderAlgorithm($complete_headers);
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        $wrapper = $this->getWrapper();
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        $hash_algorithm = $this->getHashAlgorithm();
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        $key_size = $this->getKeySize();
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        $salt = StringUtil::generateRandomBytes($this->salt_size);
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        $password = Base64Url::decode($key->get('k'));
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        // We set headers parameters
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        $additional_headers['p2s'] = Base64Url::encode($salt);
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        $additional_headers['p2c'] = $this->nb_count;
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        $derived_key = hash_pbkdf2($hash_algorithm, $password, $complete_headers['alg']."\x00".$salt, $this->nb_count, $key_size, true);
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        return $wrapper->wrap($derived_key, $cek);
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    }
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    /**
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     * {@inheritdoc}
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     */
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    public function unwrapKey(JWKInterface $key, $encrypted_cek, array $header)
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    {
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        $this->checkKey($key);
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        $this->checkHeaderAlgorithm($header);
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        $this->checkHeaderAdditionalParameters($header);
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        $wrapper = $this->getWrapper();
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        $hash_algorithm = $this->getHashAlgorithm();
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        $key_size = $this->getKeySize();
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        $salt = $header['alg']."\x00".Base64Url::decode($header['p2s']);
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        $count = $header['p2c'];
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        $password = Base64Url::decode($key->get('k'));
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        $derived_key = hash_pbkdf2($hash_algorithm, $password, $salt, $count, $key_size, true);
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        return $wrapper->unwrap($derived_key, $encrypted_cek);
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    }
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    /**
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     * {@inheritdoc}
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     */
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    public function getKeyManagementMode()
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    {
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        return self::MODE_WRAP;
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    }
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    /**
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     * @param JWKInterface $key
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     */
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    protected function checkKey(JWKInterface $key)
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    {
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        Assertion::eq($key->get('kty'), 'oct', 'Wrong key type.');
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        Assertion::true($key->has('k'), 'The key parameter "k" is missing.');
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    }
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    /**
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     * @param array $header
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     */
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    protected function checkHeaderAlgorithm(array $header)
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    {
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        Assertion::keyExists($header, 'alg', 'The header parameter "alg" is missing.');
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        Assertion::notEmpty($header['alg'], 'The header parameter "alg" is not valid.');
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    }
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    /**
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     * @param array $header
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     */
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    protected function checkHeaderAdditionalParameters(array $header)
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    {
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        Assertion::keyExists($header, 'p2s', 'The header parameter "p2s" is missing.');
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        Assertion::notEmpty($header['p2s'], 'The header parameter "p2s" is not valid.');
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        Assertion::keyExists($header, 'p2c', 'The header parameter "p2c" is missing.');
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        Assertion::notEmpty($header['p2c'], 'The header parameter "p2c" is not valid.');
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    }
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    /**
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     * @return \AESKW\A128KW|\AESKW\A192KW|\AESKW\A256KW
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     */
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    abstract protected function getWrapper();
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    /**
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     * @return string
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     */
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    abstract protected function getHashAlgorithm();
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    /**
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     * @return int
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     */
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    abstract protected function getKeySize();
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}
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