Encrypter::determineCEK() - Code Metrics - Inspection of "Logger removed and new interfaces" - Spomky-Labs/jose - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 65e224...f25ceb )

by Florent

created 2016-07-16 08:37 UTC

Encrypter::determineCEK() B

↳ Parent: Encrypter

Complexity

Conditions	5
Paths	5

Size

Total Lines	31
Code Lines	23

Duplication

Lines	0
Ratio	0 %

Importance

Changes	3
Bugs	0	Features	0

Metric	Value
c	3
b	0
f	0
dl	0
loc	31
rs	8.439
cc	5
eloc	23
nc	5
nop	4

<?php

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2016 Spomky-Labs
 *
 * This software may be modified and distributed under the terms
 * of the MIT license.  See the LICENSE file for details.
 */

namespace Jose;

use Assert\Assertion;
use Base64Url\Base64Url;
use Jose\Algorithm\ContentEncryptionAlgorithmInterface;
use Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface;
use Jose\Algorithm\KeyEncryption\KeyEncryptionInterface;
use Jose\Algorithm\KeyEncryption\KeyWrappingInterface;
use Jose\Algorithm\KeyEncryptionAlgorithmInterface;
use Jose\Behaviour\CommonCipheringMethods;
use Jose\Behaviour\HasCompressionManager;
use Jose\Behaviour\HasJWAManager;
use Jose\Behaviour\HasKeyChecker;
use Jose\Compression\CompressionInterface;
use Jose\Factory\AlgorithmManagerFactory;
use Jose\Factory\CompressionManagerFactory;
use Jose\Object\JWEInterface;
use Jose\Object\JWKInterface;
use Jose\Object\Recipient;
use Jose\Object\RecipientInterface;

final class Encrypter implements EncrypterInterface
{
    use HasKeyChecker;
    use HasJWAManager;
    use HasCompressionManager;
    use CommonCipheringMethods;

    /**
     * {@inheritdoc}
     */
    public static function createEncrypter(array $key_encryption_algorithms, array $content_encryption_algorithms, array $compression_methods = ['DEF', 'ZLIB', 'GZ'])
    {
        $encrypter = new self($key_encryption_algorithms, $content_encryption_algorithms, $compression_methods);

        return $encrypter;
    }

    /**
     * Decrypter constructor.
     *
     * @param string[]|\Jose\Algorithm\KeyEncryptionAlgorithmInterface[]     $key_encryption_algorithms
     * @param string[]|\Jose\Algorithm\ContentEncryptionAlgorithmInterface[] $content_encryption_algorithms
     * @param string[]|\Jose\Compression\CompressionInterface[]              $compression_methods
     */
    public function __construct(
        array $key_encryption_algorithms,
        array $content_encryption_algorithms,
        array $compression_methods
    ) {
        $this->setKeyEncryptionAlgorithms($key_encryption_algorithms);
        $this->setContentEncryptionAlgorithms($content_encryption_algorithms);
        $this->setCompressionMethods($compression_methods);
        $this->setJWAManager(AlgorithmManagerFactory::createAlgorithmManager(array_merge(
            $key_encryption_algorithms,
            $content_encryption_algorithms
        )));
        $this->setCompressionManager(CompressionManagerFactory::createCompressionManager($compression_methods));
    }

    /**
     * {@inheritdoc}
     */
    public function encrypt(JWEInterface &$jwe)
    {
        Assertion::false($jwe->isEncrypted(), 'The JWE is already encrypted.');
        Assertion::greaterThan($jwe->countRecipients(), 0, 'The JWE does not contain recipient.');

        // Content Encryption Algorithm
        $content_encryption_algorithm = $this->getContentEncryptionAlgorithm($jwe);

        // Compression Method
        $compression_method = $this->getCompressionMethod($jwe);

        // Key Management Mode
        $key_management_mode = $this->getKeyManagementMode($jwe);

        // Additional Headers
        $additional_headers = [];

        // CEK
        $cek = $this->determineCEK(
            $jwe,
            $content_encryption_algorithm,
            $key_management_mode,
            $additional_headers
        );

        $nb_recipients = $jwe->countRecipients();

        for ($i = 0; $i < $nb_recipients; $i++) {
            $this->processRecipient(
                $jwe,
                $jwe->getRecipient($i),
                $cek,
                $content_encryption_algorithm,
                $additional_headers
            );
        }

        if (!empty($additional_headers) && 1 === $jwe->countRecipients()) {
            $jwe = $jwe->withSharedProtectedHeaders(array_merge(
                $jwe->getSharedProtectedHeaders(),
                $additional_headers
            ));
        }

        // IV
        $iv_size = $content_encryption_algorithm->getIVSize();
        $iv = $this->createIV($iv_size);

        $this->encryptJWE($jwe, $content_encryption_algorithm, $cek, $iv, $compression_method);
    }

    /**
     * @param \Jose\Object\JWEInterface                           $jwe
     * @param \Jose\Object\RecipientInterface                     $recipient
     * @param string                                              $cek
     * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
     * @param array                                               $additional_headers
     */
    private function processRecipient(JWEInterface $jwe,
                                      RecipientInterface &$recipient,
                                      $cek,
                                      ContentEncryptionAlgorithmInterface $content_encryption_algorithm,
                                      array &$additional_headers
    ) {
        if (null === $recipient->getRecipientKey()) {

            return;
        }
        $complete_headers = array_merge(
            $jwe->getSharedProtectedHeaders(),
            $jwe->getSharedHeaders(),
            $recipient->getHeaders()
        );

        $key_encryption_algorithm = $this->findKeyEncryptionAlgorithm($complete_headers);

        // We check keys (usage and algorithm if restrictions are set)
        $this->checkKeys(
            $key_encryption_algorithm,
            $content_encryption_algorithm,
            $recipient->getRecipientKey()
        );

        $encrypted_content_encryption_key = $this->getEncryptedKey(
            $complete_headers,
            $cek,
            $key_encryption_algorithm,
            $content_encryption_algorithm,
            $additional_headers,
            $recipient->getRecipientKey()
        );

        $recipient_headers = $recipient->getHeaders();
        if (!empty($additional_headers) && 1 !== $jwe->countRecipients()) {
            $recipient_headers = array_merge(
                $recipient_headers,
                $additional_headers
            );
            $additional_headers = [];
        }

        $recipient = Recipient::createRecipientFromLoadedJWE($recipient_headers, $encrypted_content_encryption_key);
    }

    /**
     * @param \Jose\Object\JWEInterface                           $jwe
     * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
     * @param string                                              $key_management_mode
     * @param array                                               $additional_headers
     *
     * @return string
     */
    private function determineCEK(JWEInterface $jwe,
                                  ContentEncryptionAlgorithmInterface $content_encryption_algorithm,
                                  $key_management_mode,
                                  array &$additional_headers
    ) {
        switch ($key_management_mode) {
            case KeyEncryptionInterface::MODE_ENCRYPT:
            case KeyEncryptionInterface::MODE_WRAP:
                return $this->createCEK($content_encryption_algorithm->getCEKSize());
            case KeyEncryptionInterface::MODE_AGREEMENT:
                Assertion::eq(1, $jwe->countRecipients(), 'Unable to encrypt for multiple recipients using key agreement algorithms.');

                $complete_headers = array_merge(
                    $jwe->getSharedProtectedHeaders(),
                    $jwe->getSharedHeaders(),
                    $jwe->getRecipient(0)->getHeaders()
                );
                $algorithm = $this->findKeyEncryptionAlgorithm($complete_headers);

                return $algorithm->getAgreementKey($content_encryption_algorithm->getCEKSize(), $content_encryption_algorithm->getAlgorithmName(), $jwe->getRecipient(0)->getRecipientKey(), $complete_headers, $additional_headers);
            case KeyEncryptionInterface::MODE_DIRECT:
                Assertion::eq(1, $jwe->countRecipients(), 'Unable to encrypt for multiple recipients using key agreement algorithms.');

                Assertion::eq($jwe->getRecipient(0)->getRecipientKey()->get('kty'), 'oct', 'Wrong key type.');
                Assertion::true($jwe->getRecipient(0)->getRecipientKey()->has('k'), 'The key parameter "k" is missing.');

                return Base64Url::decode($jwe->getRecipient(0)->getRecipientKey()->get('k'));
            default:
                throw new \InvalidArgumentException(sprintf('Unsupported key management mode "%s".', $key_management_mode));
        }
    }

    /**
     * @param \Jose\Object\JWEInterface $jwe
     *
     * @return string
     */
    private function getKeyManagementMode(JWEInterface $jwe)
    {
        $mode = null;
        $recipients = $jwe->getRecipients();

        foreach ($recipients as $recipient) {
            $complete_headers = array_merge(
                $jwe->getSharedProtectedHeaders(),
                $jwe->getSharedHeaders(),
                $recipient->getHeaders()
            );
            Assertion::keyExists($complete_headers, 'alg', 'Parameter "alg" is missing.');

            $key_encryption_algorithm = $this->getJWAManager()->getAlgorithm($complete_headers['alg']);
            Assertion::isInstanceOf($key_encryption_algorithm, KeyEncryptionAlgorithmInterface::class, sprintf('The key encryption algorithm "%s" is not supported or not a key encryption algorithm instance.', $complete_headers['alg']));

            if (null === $mode) {
                $mode = $key_encryption_algorithm->getKeyManagementMode();
            } else {
                Assertion::true(
                    $this->areKeyManagementModesCompatible($mode, $key_encryption_algorithm->getKeyManagementMode()),
                    'Foreign key management mode forbidden.'
                );
            }
        }

        return $mode;
    }

    /**
     * @param \Jose\Object\JWEInterface $jwe
     *
     * @return \Jose\Compression\CompressionInterface|null
     */
    private function getCompressionMethod(JWEInterface $jwe)
    {
        $method = null;
        $nb_recipients = $jwe->countRecipients();

        for ($i = 0; $i < $nb_recipients; $i++) {
            $complete_headers = array_merge(
                $jwe->getSharedProtectedHeaders(),
                $jwe->getSharedHeaders(),
                $jwe->getRecipient($i)->getHeaders()
            );
            if (array_key_exists('zip', $complete_headers)) {
                if (null === $method) {
                    if (0 === $i) {
                        $method = $complete_headers['zip'];
                    } else {
                        throw new \InvalidArgumentException('Inconsistent "zip" parameter.');
                    }
                } else {
                    Assertion::eq($method, $complete_headers['zip'], 'Inconsistent "zip" parameter.');
                }
            } else {
                Assertion::eq(null, $method, 'Inconsistent "zip" parameter.');
            }
        }

        if (null === $method) {
            return;
        }

        $compression_method = $this->getCompressionManager()->getCompressionAlgorithm($method);
        Assertion::isInstanceOf($compression_method, CompressionInterface::class, sprintf('Compression method "%s" not supported.', $method));

        return $compression_method;
    }

    /**
     * @param \Jose\Object\JWEInterface $jwe
     *
     * @return \Jose\Algorithm\ContentEncryptionAlgorithmInterface
     */
    private function getContentEncryptionAlgorithm(JWEInterface $jwe)
    {
        $algorithm = null;

        foreach ($jwe->getRecipients() as $recipient) {
            $complete_headers = array_merge(
                $jwe->getSharedProtectedHeaders(),
                $jwe->getSharedHeaders(),
                $recipient->getHeaders()
            );
            Assertion::keyExists($complete_headers, 'enc', 'Parameter "enc" is missing.');
            if (null === $algorithm) {
                $algorithm = $complete_headers['enc'];
            } else {
                Assertion::eq($algorithm, $complete_headers['enc'], 'Foreign content encryption algorithms are not allowed.');
            }
        }

        $content_encryption_algorithm = $this->getJWAManager()->getAlgorithm($algorithm);
        Assertion::isInstanceOf($content_encryption_algorithm, ContentEncryptionAlgorithmInterface::class, sprintf('The content encryption algorithm "%s" is not supported or not a content encryption algorithm instance.', $algorithm));

        return $content_encryption_algorithm;
    }

    /**
     * @param \Jose\Object\JWEInterface                           $jwe
     * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
     * @param string                                              $cek
     * @param string                                              $iv
     * @param \Jose\Compression\CompressionInterface|null         $compression_method
     */
    private function encryptJWE(JWEInterface &$jwe,
                                ContentEncryptionAlgorithmInterface $content_encryption_algorithm,
                                $cek,
                                $iv,
                                CompressionInterface $compression_method = null
    ) {
        if (!empty($jwe->getSharedProtectedHeaders())) {
            $jwe = $jwe->withEncodedSharedProtectedHeaders(Base64Url::encode(json_encode($jwe->getSharedProtectedHeaders())));
        }

        // We encrypt the payload and get the tag
        $tag = null;
        $payload = $this->preparePayload($jwe->getPayload(), $compression_method);

        $ciphertext = $content_encryption_algorithm->encryptContent(
            $payload,
            $cek,
            $iv,
            null === $jwe->getAAD() ? null : Base64Url::encode($jwe->getAAD()),
            $jwe->getEncodedSharedProtectedHeaders(),
            $tag
        );

        $jwe = $jwe->withCiphertext($ciphertext);
        $jwe = $jwe->withIV($iv);

        // Tag
        if (null !== $tag) {
            $jwe = $jwe->withTag($tag);
        }
    }

    /**
     * @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface     $key_encryption_algorithm
     * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
     * @param \Jose\Object\JWKInterface                           $recipient_key
     */
    private function checkKeys(KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, JWKInterface $recipient_key)
    {
        $this->checkKeyUsage($recipient_key, 'encryption');
        if ('dir' !== $key_encryption_algorithm->getAlgorithmName()) {
            $this->checkKeyAlgorithm($recipient_key, $key_encryption_algorithm->getAlgorithmName());
        } else {
            $this->checkKeyAlgorithm($recipient_key, $content_encryption_algorithm->getAlgorithmName());
        }
    }

    /**
     * @param string $current
     * @param string $new
     *
     * @return bool
     */
    private function areKeyManagementModesCompatible($current, $new)
    {
        $agree = KeyEncryptionAlgorithmInterface::MODE_AGREEMENT;
        $dir = KeyEncryptionAlgorithmInterface::MODE_DIRECT;
        $enc = KeyEncryptionAlgorithmInterface::MODE_ENCRYPT;
        $wrap = KeyEncryptionAlgorithmInterface::MODE_WRAP;

        $supported_key_management_mode_combinations = [
            $enc.$enc     => true,
            $enc.$wrap    => true,
            $wrap.$enc    => true,
            $wrap.$wrap   => true,
            $agree.$agree => false,
            $agree.$dir   => false,
            $agree.$enc   => false,
            $agree.$wrap  => false,
            $dir.$agree   => false,
            $dir.$dir     => false,
            $dir.$enc     => false,
            $dir.$wrap    => false,
            $enc.$agree   => false,
            $enc.$dir     => false,
            $wrap.$agree  => false,
            $wrap.$dir    => false,
        ];

        if (array_key_exists($current.$new, $supported_key_management_mode_combinations)) {
            return $supported_key_management_mode_combinations[$current.$new];
        }

        return false;
    }

    /**
     * @param string                                      $payload
     * @param \Jose\Compression\CompressionInterface|null $compression_method
     *
     * @return string
     */
    private function preparePayload($payload, CompressionInterface $compression_method = null)
    {
        $prepared = is_string($payload) ? $payload : json_encode($payload);

        Assertion::notNull($prepared, 'The payload is empty or cannot encoded into JSON.');

        if (null === $compression_method) {
            return $prepared;
        }
        $compressed_payload = $compression_method->compress($prepared);
        Assertion::string($compressed_payload, 'Compression failed.');

        return $compressed_payload;
    }

    /**
     * @param array                                               $complete_headers
     * @param string                                              $cek
     * @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface     $key_encryption_algorithm
     * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
     * @param \Jose\Object\JWKInterface                           $recipient_key
     * @param array                                               $additional_headers
     *
     * @return string|null
     */
    private function getEncryptedKey(array $complete_headers, $cek, KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key)
    {
        if ($key_encryption_algorithm instanceof KeyEncryptionInterface) {
            return $this->getEncryptedKeyFromKeyEncryptionAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $recipient_key, $additional_headers);
        } elseif ($key_encryption_algorithm instanceof KeyWrappingInterface) {
            return $this->getEncryptedKeyFromKeyWrappingAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $recipient_key, $additional_headers);
        } elseif ($key_encryption_algorithm instanceof KeyAgreementWrappingInterface) {
            return $this->getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $content_encryption_algorithm, $additional_headers, $recipient_key);
        }

        // Using KeyAgreementInterface or DirectEncryptionInterface, the encrypted key is an empty string
    }

    /**
     * @param array                                                       $complete_headers
     * @param string                                                      $cek
     * @param \Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface $key_encryption_algorithm
     * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface         $content_encryption_algorithm
     * @param array                                                       $additional_headers
     * @param \Jose\Object\JWKInterface                                   $recipient_key
     *
     * @return string
     */
    private function getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm(array $complete_headers, $cek, KeyAgreementWrappingInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key)
    {
        $jwt_cek = $key_encryption_algorithm->wrapAgreementKey($recipient_key, $cek, $content_encryption_algorithm->getCEKSize(), $complete_headers, $additional_headers);

        return $jwt_cek;
    }

    /**
     * @param array                                                $complete_headers
     * @param string                                               $cek
     * @param \Jose\Algorithm\KeyEncryption\KeyEncryptionInterface $key_encryption_algorithm
     * @param \Jose\Object\JWKInterface                            $recipient_key
     * @param array                                                $additional_headers
     *
     * @return string
     */
    private function getEncryptedKeyFromKeyEncryptionAlgorithm(array $complete_headers, $cek, KeyEncryptionInterface $key_encryption_algorithm, JWKInterface $recipient_key, array &$additional_headers)
    {
        return $key_encryption_algorithm->encryptKey(
            $recipient_key,
            $cek,
            $complete_headers,
            $additional_headers
        );
    }

    /**
     * @param array                                              $complete_headers
     * @param string                                             $cek
     * @param \Jose\Algorithm\KeyEncryption\KeyWrappingInterface $key_encryption_algorithm
     * @param \Jose\Object\JWKInterface                          $recipient_key
     * @param array                                              $additional_headers
     *
     * @return string
     */
    private function getEncryptedKeyFromKeyWrappingAlgorithm(array $complete_headers, $cek, KeyWrappingInterface $key_encryption_algorithm, JWKInterface $recipient_key, &$additional_headers)
    {
        return $key_encryption_algorithm->wrapKey(
            $recipient_key,
            $cek,
            $complete_headers,
            $additional_headers
        );
    }

    /**
     * @param array $complete_headers
     *
     * @return \Jose\Algorithm\KeyEncryptionAlgorithmInterface
     */
    private function findKeyEncryptionAlgorithm(array $complete_headers)
    {
        Assertion::keyExists($complete_headers, 'alg', 'Parameter "alg" is missing.');

        $key_encryption_algorithm = $this->getJWAManager()->getAlgorithm($complete_headers['alg']);
        Assertion::isInstanceOf($key_encryption_algorithm, KeyEncryptionAlgorithmInterface::class, sprintf('The key encryption algorithm "%s" is not supported or not a key encryption algorithm instance.', $complete_headers['alg']));

        return $key_encryption_algorithm;
    }

    /**
     * @param int $size
     *
     * @return string
     */
    private function createCEK($size)
    {
        return random_bytes($size / 8);
    }

    /**
     * @param int $size
     *
     * @return string
     */
    private function createIV($size)
    {
        return random_bytes($size / 8);
    }
}


1			<?php
2
3			/*
4			* The MIT License (MIT)
5			*
6			* Copyright (c) 2014-2016 Spomky-Labs
7			*
8			* This software may be modified and distributed under the terms
9			* of the MIT license. See the LICENSE file for details.
10			*/
11
12			namespace Jose;
13
14			use Assert\Assertion;
15			use Base64Url\Base64Url;
16			use Jose\Algorithm\ContentEncryptionAlgorithmInterface;
17			use Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface;
18			use Jose\Algorithm\KeyEncryption\KeyEncryptionInterface;
19			use Jose\Algorithm\KeyEncryption\KeyWrappingInterface;
20			use Jose\Algorithm\KeyEncryptionAlgorithmInterface;
21			use Jose\Behaviour\CommonCipheringMethods;
22			use Jose\Behaviour\HasCompressionManager;
23			use Jose\Behaviour\HasJWAManager;
24			use Jose\Behaviour\HasKeyChecker;
25			use Jose\Compression\CompressionInterface;
26			use Jose\Factory\AlgorithmManagerFactory;
27			use Jose\Factory\CompressionManagerFactory;
28			use Jose\Object\JWEInterface;
29			use Jose\Object\JWKInterface;
30			use Jose\Object\Recipient;
31			use Jose\Object\RecipientInterface;
32
33			final class Encrypter implements EncrypterInterface
34			{
35			use HasKeyChecker;
36			use HasJWAManager;
37			use HasCompressionManager;
38			use CommonCipheringMethods;
39
40			/**
41			* {@inheritdoc}
42			*/
43			public static function createEncrypter(array $key_encryption_algorithms, array $content_encryption_algorithms, array $compression_methods = ['DEF', 'ZLIB', 'GZ'])
44			{
45			$encrypter = new self($key_encryption_algorithms, $content_encryption_algorithms, $compression_methods);
46
47			return $encrypter;
48			}
49
50			/**
51			* Decrypter constructor.
52			*
53			* @param string[]\|\Jose\Algorithm\KeyEncryptionAlgorithmInterface[] $key_encryption_algorithms
54			* @param string[]\|\Jose\Algorithm\ContentEncryptionAlgorithmInterface[] $content_encryption_algorithms
55			* @param string[]\|\Jose\Compression\CompressionInterface[] $compression_methods
56			*/
57			public function __construct(
58			array $key_encryption_algorithms,
59			array $content_encryption_algorithms,
60			array $compression_methods
61			) {
62			$this->setKeyEncryptionAlgorithms($key_encryption_algorithms);
63			$this->setContentEncryptionAlgorithms($content_encryption_algorithms);
64			$this->setCompressionMethods($compression_methods);
65			$this->setJWAManager(AlgorithmManagerFactory::createAlgorithmManager(array_merge(
66			$key_encryption_algorithms,
67			$content_encryption_algorithms
68			)));
69			$this->setCompressionManager(CompressionManagerFactory::createCompressionManager($compression_methods));
70			}
71
72			/**
73			* {@inheritdoc}
74			*/
75			public function encrypt(JWEInterface &$jwe)
76			{
77			Assertion::false($jwe->isEncrypted(), 'The JWE is already encrypted.');
78			Assertion::greaterThan($jwe->countRecipients(), 0, 'The JWE does not contain recipient.');
79
80			// Content Encryption Algorithm
81			$content_encryption_algorithm = $this->getContentEncryptionAlgorithm($jwe);
82
83			// Compression Method
84			$compression_method = $this->getCompressionMethod($jwe);
85
86			// Key Management Mode
87			$key_management_mode = $this->getKeyManagementMode($jwe);
88
89			// Additional Headers
90			$additional_headers = [];
91
92			// CEK
93			$cek = $this->determineCEK(
94			$jwe,
95			$content_encryption_algorithm,
96			$key_management_mode,
97			$additional_headers
98			);
99
100			$nb_recipients = $jwe->countRecipients();
101
102			for ($i = 0; $i < $nb_recipients; $i++) {
103			$this->processRecipient(
104			$jwe,
105			$jwe->getRecipient($i),
106			$cek,
107			$content_encryption_algorithm,
108			$additional_headers
109			);
110			}
111
112			if (!empty($additional_headers) && 1 === $jwe->countRecipients()) {
113			$jwe = $jwe->withSharedProtectedHeaders(array_merge(
114			$jwe->getSharedProtectedHeaders(),
115			$additional_headers
116			));
117			}
118
119			// IV
120			$iv_size = $content_encryption_algorithm->getIVSize();
121			$iv = $this->createIV($iv_size);
122
123			$this->encryptJWE($jwe, $content_encryption_algorithm, $cek, $iv, $compression_method);
124			}
125
126			/**
127			* @param \Jose\Object\JWEInterface $jwe
128			* @param \Jose\Object\RecipientInterface $recipient
129			* @param string $cek
130			* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
131			* @param array $additional_headers
132			*/
133			private function processRecipient(JWEInterface $jwe,
134			RecipientInterface &$recipient,
135			$cek,
136			ContentEncryptionAlgorithmInterface $content_encryption_algorithm,
137			array &$additional_headers
138			) {
139			if (null === $recipient->getRecipientKey()) {
140
141			return;
142			}
143			$complete_headers = array_merge(
144			$jwe->getSharedProtectedHeaders(),
145			$jwe->getSharedHeaders(),
146			$recipient->getHeaders()
147			);
148
149			$key_encryption_algorithm = $this->findKeyEncryptionAlgorithm($complete_headers);
150
151			// We check keys (usage and algorithm if restrictions are set)
152			$this->checkKeys(
153			$key_encryption_algorithm,
154			$content_encryption_algorithm,
155			$recipient->getRecipientKey()
156			);
157
158			$encrypted_content_encryption_key = $this->getEncryptedKey(
159			$complete_headers,
160			$cek,
161			$key_encryption_algorithm,
162			$content_encryption_algorithm,
163			$additional_headers,
164			$recipient->getRecipientKey()
165			);
166
167			$recipient_headers = $recipient->getHeaders();
168			if (!empty($additional_headers) && 1 !== $jwe->countRecipients()) {
169			$recipient_headers = array_merge(
170			$recipient_headers,
171			$additional_headers
172			);
173			$additional_headers = [];
174			}
175
176			$recipient = Recipient::createRecipientFromLoadedJWE($recipient_headers, $encrypted_content_encryption_key);
177			}
178
179			/**
180			* @param \Jose\Object\JWEInterface $jwe
181			* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
182			* @param string $key_management_mode
183			* @param array $additional_headers
184			*
185			* @return string
186			*/
187			private function determineCEK(JWEInterface $jwe,
188			ContentEncryptionAlgorithmInterface $content_encryption_algorithm,
189			$key_management_mode,
190			array &$additional_headers
191			) {
192			switch ($key_management_mode) {
193			case KeyEncryptionInterface::MODE_ENCRYPT:
194			case KeyEncryptionInterface::MODE_WRAP:
195			return $this->createCEK($content_encryption_algorithm->getCEKSize());
196			case KeyEncryptionInterface::MODE_AGREEMENT:
197			Assertion::eq(1, $jwe->countRecipients(), 'Unable to encrypt for multiple recipients using key agreement algorithms.');
198
199			$complete_headers = array_merge(
200			$jwe->getSharedProtectedHeaders(),
201			$jwe->getSharedHeaders(),
202			$jwe->getRecipient(0)->getHeaders()
203			);
204			$algorithm = $this->findKeyEncryptionAlgorithm($complete_headers);
205
206			return $algorithm->getAgreementKey($content_encryption_algorithm->getCEKSize(), $content_encryption_algorithm->getAlgorithmName(), $jwe->getRecipient(0)->getRecipientKey(), $complete_headers, $additional_headers);
207			case KeyEncryptionInterface::MODE_DIRECT:
208			Assertion::eq(1, $jwe->countRecipients(), 'Unable to encrypt for multiple recipients using key agreement algorithms.');
209
210			Assertion::eq($jwe->getRecipient(0)->getRecipientKey()->get('kty'), 'oct', 'Wrong key type.');
211			Assertion::true($jwe->getRecipient(0)->getRecipientKey()->has('k'), 'The key parameter "k" is missing.');
212
213			return Base64Url::decode($jwe->getRecipient(0)->getRecipientKey()->get('k'));
214			default:
215			throw new \InvalidArgumentException(sprintf('Unsupported key management mode "%s".', $key_management_mode));
216			}
217			}
218
219			/**
220			* @param \Jose\Object\JWEInterface $jwe
221			*
222			* @return string
223			*/
224			private function getKeyManagementMode(JWEInterface $jwe)
225			{
226			$mode = null;
227			$recipients = $jwe->getRecipients();
228
229			foreach ($recipients as $recipient) {
230			$complete_headers = array_merge(
231			$jwe->getSharedProtectedHeaders(),
232			$jwe->getSharedHeaders(),
233			$recipient->getHeaders()
234			);
235			Assertion::keyExists($complete_headers, 'alg', 'Parameter "alg" is missing.');
236
237			$key_encryption_algorithm = $this->getJWAManager()->getAlgorithm($complete_headers['alg']);
238			Assertion::isInstanceOf($key_encryption_algorithm, KeyEncryptionAlgorithmInterface::class, sprintf('The key encryption algorithm "%s" is not supported or not a key encryption algorithm instance.', $complete_headers['alg']));
239
240			if (null === $mode) {
241			$mode = $key_encryption_algorithm->getKeyManagementMode();
242			} else {
243			Assertion::true(
244			$this->areKeyManagementModesCompatible($mode, $key_encryption_algorithm->getKeyManagementMode()),
245			'Foreign key management mode forbidden.'
246			);
247			}
248			}
249
250			return $mode;
251			}
252
253			/**
254			* @param \Jose\Object\JWEInterface $jwe
255			*
256			* @return \Jose\Compression\CompressionInterface\|null
257			*/
258			private function getCompressionMethod(JWEInterface $jwe)
259			{
260			$method = null;
261			$nb_recipients = $jwe->countRecipients();
262
263			for ($i = 0; $i < $nb_recipients; $i++) {
264			$complete_headers = array_merge(
265			$jwe->getSharedProtectedHeaders(),
266			$jwe->getSharedHeaders(),
267			$jwe->getRecipient($i)->getHeaders()
268			);
269			if (array_key_exists('zip', $complete_headers)) {
270			if (null === $method) {
271			if (0 === $i) {
272			$method = $complete_headers['zip'];
273			} else {
274			throw new \InvalidArgumentException('Inconsistent "zip" parameter.');
275			}
276			} else {
277			Assertion::eq($method, $complete_headers['zip'], 'Inconsistent "zip" parameter.');
278			}
279			} else {
280			Assertion::eq(null, $method, 'Inconsistent "zip" parameter.');
281			}
282			}
283
284			if (null === $method) {
285			return;
286			}
287
288			$compression_method = $this->getCompressionManager()->getCompressionAlgorithm($method);
289			Assertion::isInstanceOf($compression_method, CompressionInterface::class, sprintf('Compression method "%s" not supported.', $method));
290
291			return $compression_method;
292			}
293
294			/**
295			* @param \Jose\Object\JWEInterface $jwe
296			*
297			* @return \Jose\Algorithm\ContentEncryptionAlgorithmInterface
298			*/
299			private function getContentEncryptionAlgorithm(JWEInterface $jwe)
300			{
301			$algorithm = null;
302
303			foreach ($jwe->getRecipients() as $recipient) {
304			$complete_headers = array_merge(
305			$jwe->getSharedProtectedHeaders(),
306			$jwe->getSharedHeaders(),
307			$recipient->getHeaders()
308			);
309			Assertion::keyExists($complete_headers, 'enc', 'Parameter "enc" is missing.');
310			if (null === $algorithm) {
311			$algorithm = $complete_headers['enc'];
312			} else {
313			Assertion::eq($algorithm, $complete_headers['enc'], 'Foreign content encryption algorithms are not allowed.');
314			}
315			}
316
317			$content_encryption_algorithm = $this->getJWAManager()->getAlgorithm($algorithm);
318			Assertion::isInstanceOf($content_encryption_algorithm, ContentEncryptionAlgorithmInterface::class, sprintf('The content encryption algorithm "%s" is not supported or not a content encryption algorithm instance.', $algorithm));
319
320			return $content_encryption_algorithm;
321			}
322
323			/**
324			* @param \Jose\Object\JWEInterface $jwe
325			* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
326			* @param string $cek
327			* @param string $iv
328			* @param \Jose\Compression\CompressionInterface\|null $compression_method
329			*/
330			private function encryptJWE(JWEInterface &$jwe,
331			ContentEncryptionAlgorithmInterface $content_encryption_algorithm,
332			$cek,
333			$iv,
334			CompressionInterface $compression_method = null
335			) {
336			if (!empty($jwe->getSharedProtectedHeaders())) {
337			$jwe = $jwe->withEncodedSharedProtectedHeaders(Base64Url::encode(json_encode($jwe->getSharedProtectedHeaders())));
338			}
339
340			// We encrypt the payload and get the tag
341			$tag = null;
342			$payload = $this->preparePayload($jwe->getPayload(), $compression_method);
343
344			$ciphertext = $content_encryption_algorithm->encryptContent(
345			$payload,
346			$cek,
347			$iv,
348			null === $jwe->getAAD() ? null : Base64Url::encode($jwe->getAAD()),
349			$jwe->getEncodedSharedProtectedHeaders(),
350			$tag
351			);
352
353			$jwe = $jwe->withCiphertext($ciphertext);
354			$jwe = $jwe->withIV($iv);
355
356			// Tag
357			if (null !== $tag) {
358			$jwe = $jwe->withTag($tag);
359			}
360			}
361
362			/**
363			* @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface $key_encryption_algorithm
364			* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
365			* @param \Jose\Object\JWKInterface $recipient_key
366			*/
367			private function checkKeys(KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, JWKInterface $recipient_key)
368			{
369			$this->checkKeyUsage($recipient_key, 'encryption');
370			if ('dir' !== $key_encryption_algorithm->getAlgorithmName()) {
371			$this->checkKeyAlgorithm($recipient_key, $key_encryption_algorithm->getAlgorithmName());
372			} else {
373			$this->checkKeyAlgorithm($recipient_key, $content_encryption_algorithm->getAlgorithmName());
374			}
375			}
376
377			/**
378			* @param string $current
379			* @param string $new
380			*
381			* @return bool
382			*/
383			private function areKeyManagementModesCompatible($current, $new)
384			{
385			$agree = KeyEncryptionAlgorithmInterface::MODE_AGREEMENT;
386			$dir = KeyEncryptionAlgorithmInterface::MODE_DIRECT;
387			$enc = KeyEncryptionAlgorithmInterface::MODE_ENCRYPT;
388			$wrap = KeyEncryptionAlgorithmInterface::MODE_WRAP;
389
390			$supported_key_management_mode_combinations = [
391			$enc.$enc => true,
392			$enc.$wrap => true,
393			$wrap.$enc => true,
394			$wrap.$wrap => true,
395			$agree.$agree => false,
396			$agree.$dir => false,
397			$agree.$enc => false,
398			$agree.$wrap => false,
399			$dir.$agree => false,
400			$dir.$dir => false,
401			$dir.$enc => false,
402			$dir.$wrap => false,
403			$enc.$agree => false,
404			$enc.$dir => false,
405			$wrap.$agree => false,
406			$wrap.$dir => false,
407			];
408
409			if (array_key_exists($current.$new, $supported_key_management_mode_combinations)) {
410			return $supported_key_management_mode_combinations[$current.$new];
411			}
412
413			return false;
414			}
415
416			/**
417			* @param string $payload
418			* @param \Jose\Compression\CompressionInterface\|null $compression_method
419			*
420			* @return string
421			*/
422			private function preparePayload($payload, CompressionInterface $compression_method = null)
423			{
424			$prepared = is_string($payload) ? $payload : json_encode($payload);
425
426			Assertion::notNull($prepared, 'The payload is empty or cannot encoded into JSON.');
427
428			if (null === $compression_method) {
429			return $prepared;
430			}
431			$compressed_payload = $compression_method->compress($prepared);
432			Assertion::string($compressed_payload, 'Compression failed.');
433
434			return $compressed_payload;
435			}
436
437			/**
438			* @param array $complete_headers
439			* @param string $cek
440			* @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface $key_encryption_algorithm
441			* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
442			* @param \Jose\Object\JWKInterface $recipient_key
443			* @param array $additional_headers
444			*
445			* @return string\|null
446			*/
447			private function getEncryptedKey(array $complete_headers, $cek, KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key)
448			{
449			if ($key_encryption_algorithm instanceof KeyEncryptionInterface) {
450			return $this->getEncryptedKeyFromKeyEncryptionAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $recipient_key, $additional_headers);
451			} elseif ($key_encryption_algorithm instanceof KeyWrappingInterface) {
452			return $this->getEncryptedKeyFromKeyWrappingAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $recipient_key, $additional_headers);
453			} elseif ($key_encryption_algorithm instanceof KeyAgreementWrappingInterface) {
454			return $this->getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $content_encryption_algorithm, $additional_headers, $recipient_key);
455			}
456
457			// Using KeyAgreementInterface or DirectEncryptionInterface, the encrypted key is an empty string
458			}
459
460			/**
461			* @param array $complete_headers
462			* @param string $cek
463			* @param \Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface $key_encryption_algorithm
464			* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm
465			* @param array $additional_headers
466			* @param \Jose\Object\JWKInterface $recipient_key
467			*
468			* @return string
469			*/
470			private function getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm(array $complete_headers, $cek, KeyAgreementWrappingInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key)
471			{
472			$jwt_cek = $key_encryption_algorithm->wrapAgreementKey($recipient_key, $cek, $content_encryption_algorithm->getCEKSize(), $complete_headers, $additional_headers);
473
474			return $jwt_cek;
475			}
476
477			/**
478			* @param array $complete_headers
479			* @param string $cek
480			* @param \Jose\Algorithm\KeyEncryption\KeyEncryptionInterface $key_encryption_algorithm
481			* @param \Jose\Object\JWKInterface $recipient_key
482			* @param array $additional_headers
483			*
484			* @return string
485			*/
486			private function getEncryptedKeyFromKeyEncryptionAlgorithm(array $complete_headers, $cek, KeyEncryptionInterface $key_encryption_algorithm, JWKInterface $recipient_key, array &$additional_headers)
487			{
488			return $key_encryption_algorithm->encryptKey(
489			$recipient_key,
490			$cek,
491			$complete_headers,
492			$additional_headers
493			);
494			}
495
496			/**
497			* @param array $complete_headers
498			* @param string $cek
499			* @param \Jose\Algorithm\KeyEncryption\KeyWrappingInterface $key_encryption_algorithm
500			* @param \Jose\Object\JWKInterface $recipient_key
501			* @param array $additional_headers
502			*
503			* @return string
504			*/
505			private function getEncryptedKeyFromKeyWrappingAlgorithm(array $complete_headers, $cek, KeyWrappingInterface $key_encryption_algorithm, JWKInterface $recipient_key, &$additional_headers)
506			{
507			return $key_encryption_algorithm->wrapKey(
508			$recipient_key,
509			$cek,
510			$complete_headers,
511			$additional_headers
512			);
513			}
514
515			/**
516			* @param array $complete_headers
517			*
518			* @return \Jose\Algorithm\KeyEncryptionAlgorithmInterface
519			*/
520			private function findKeyEncryptionAlgorithm(array $complete_headers)
521			{
522			Assertion::keyExists($complete_headers, 'alg', 'Parameter "alg" is missing.');
523
524			$key_encryption_algorithm = $this->getJWAManager()->getAlgorithm($complete_headers['alg']);
525			Assertion::isInstanceOf($key_encryption_algorithm, KeyEncryptionAlgorithmInterface::class, sprintf('The key encryption algorithm "%s" is not supported or not a key encryption algorithm instance.', $complete_headers['alg']));
526
527			return $key_encryption_algorithm;
528			}
529
530			/**
531			* @param int $size
532			*
533			* @return string
534			*/
535			private function createCEK($size)
536			{
537			return random_bytes($size / 8);
538			}
539
540			/**
541			* @param int $size
542			*
543			* @return string
544			*/
545			private function createIV($size)
546			{
547			return random_bytes($size / 8);
548			}
549			}
550

Spomky-Labs / jose

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Encrypter::determineCEK() B

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