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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; |
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use Assert\Assertion; |
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use Base64Url\Base64Url; |
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use Jose\Algorithm\ContentEncryptionAlgorithmInterface; |
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use Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface; |
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use Jose\Algorithm\KeyEncryption\KeyEncryptionInterface; |
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use Jose\Algorithm\KeyEncryption\KeyWrappingInterface; |
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use Jose\Algorithm\KeyEncryptionAlgorithmInterface; |
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use Jose\Behaviour\CommonCipheringMethods; |
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use Jose\Behaviour\HasCompressionManager; |
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use Jose\Behaviour\HasJWAManager; |
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use Jose\Behaviour\HasKeyChecker; |
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use Jose\Compression\CompressionInterface; |
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use Jose\Factory\AlgorithmManagerFactory; |
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use Jose\Factory\CompressionManagerFactory; |
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use Jose\Object\JWEInterface; |
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use Jose\Object\JWKInterface; |
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use Jose\Object\Recipient; |
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use Jose\Object\RecipientInterface; |
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final class Encrypter implements EncrypterInterface |
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{ |
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use HasKeyChecker; |
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use HasJWAManager; |
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use HasCompressionManager; |
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use CommonCipheringMethods; |
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/** |
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* {@inheritdoc} |
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*/ |
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public static function createEncrypter(array $key_encryption_algorithms, array $content_encryption_algorithms, array $compression_methods = ['DEF', 'ZLIB', 'GZ']) |
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{ |
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$encrypter = new self($key_encryption_algorithms, $content_encryption_algorithms, $compression_methods); |
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return $encrypter; |
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} |
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/** |
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* Decrypter constructor. |
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* |
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* @param string[]|\Jose\Algorithm\KeyEncryptionAlgorithmInterface[] $key_encryption_algorithms |
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* @param string[]|\Jose\Algorithm\ContentEncryptionAlgorithmInterface[] $content_encryption_algorithms |
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* @param string[]|\Jose\Compression\CompressionInterface[] $compression_methods |
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*/ |
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public function __construct(array $key_encryption_algorithms, array $content_encryption_algorithms, array $compression_methods) |
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{ |
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$this->setKeyEncryptionAlgorithms($key_encryption_algorithms); |
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$this->setContentEncryptionAlgorithms($content_encryption_algorithms); |
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$this->setCompressionMethods($compression_methods); |
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$this->setJWAManager(AlgorithmManagerFactory::createAlgorithmManager(array_merge($key_encryption_algorithms, $content_encryption_algorithms))); |
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$this->setCompressionManager(CompressionManagerFactory::createCompressionManager($compression_methods)); |
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} |
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/** |
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* {@inheritdoc} |
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*/ |
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public function encrypt(JWEInterface &$jwe) |
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{ |
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Assertion::false($jwe->isEncrypted(), 'The JWE is already encrypted.'); |
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Assertion::greaterThan($jwe->countRecipients(), 0, 'The JWE does not contain recipient.'); |
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$content_encryption_algorithm = $this->getContentEncryptionAlgorithm($jwe); |
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$compression_method = $this->getCompressionMethod($jwe); |
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$key_management_mode = $this->getKeyManagementMode($jwe); |
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$additional_headers = []; |
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$cek = $this->determineCEK($jwe, $content_encryption_algorithm, $key_management_mode, $additional_headers); |
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$nb_recipients = $jwe->countRecipients(); |
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for ($i = 0; $i < $nb_recipients; $i++) { |
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$this->processRecipient($jwe, $jwe->getRecipient($i), $cek, $content_encryption_algorithm, $additional_headers); |
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} |
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if (!empty($additional_headers) && 1 === $jwe->countRecipients()) { |
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$jwe = $jwe->withSharedProtectedHeaders(array_merge($jwe->getSharedProtectedHeaders(), $additional_headers)); |
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} |
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$iv_size = $content_encryption_algorithm->getIVSize(); |
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$iv = $this->createIV($iv_size); |
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$this->encryptJWE($jwe, $content_encryption_algorithm, $cek, $iv, $compression_method); |
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} |
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/** |
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* @param \Jose\Object\JWEInterface $jwe |
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* @param \Jose\Object\RecipientInterface $recipient |
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* @param string $cek |
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* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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* @param array $additional_headers |
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*/ |
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private function processRecipient(JWEInterface $jwe, RecipientInterface &$recipient, $cek, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers) |
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{ |
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if (null === $recipient->getRecipientKey()) { |
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return; |
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} |
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$complete_headers = array_merge($jwe->getSharedProtectedHeaders(), $jwe->getSharedHeaders(), $recipient->getHeaders()); |
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$key_encryption_algorithm = $this->findKeyEncryptionAlgorithm($complete_headers); |
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$this->checkKeys($key_encryption_algorithm, $content_encryption_algorithm, $recipient->getRecipientKey()); |
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$encrypted_content_encryption_key = $this->getEncryptedKey($complete_headers, $cek, $key_encryption_algorithm, $content_encryption_algorithm, $additional_headers, $recipient->getRecipientKey()); |
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$recipient_headers = $recipient->getHeaders(); |
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if (!empty($additional_headers) && 1 !== $jwe->countRecipients()) { |
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$recipient_headers = array_merge($recipient_headers, $additional_headers); |
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$additional_headers = []; |
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} |
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$recipient = Recipient::createRecipientFromLoadedJWE($recipient_headers, $encrypted_content_encryption_key); |
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} |
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/** |
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* @param \Jose\Object\JWEInterface $jwe |
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* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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* @param string $key_management_mode |
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* @param array $additional_headers |
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* |
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* @return string |
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*/ |
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private function determineCEK(JWEInterface $jwe, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, $key_management_mode, array &$additional_headers) |
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{ |
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switch ($key_management_mode) { |
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case KeyEncryptionInterface::MODE_ENCRYPT: |
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case KeyEncryptionInterface::MODE_WRAP: |
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return $this->createCEK($content_encryption_algorithm->getCEKSize()); |
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case KeyEncryptionInterface::MODE_AGREEMENT: |
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Assertion::eq(1, $jwe->countRecipients(), 'Unable to encrypt for multiple recipients using key agreement algorithms.'); |
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$complete_headers = array_merge($jwe->getSharedProtectedHeaders(), $jwe->getSharedHeaders(), $jwe->getRecipient(0)->getHeaders()); |
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$algorithm = $this->findKeyEncryptionAlgorithm($complete_headers); |
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return $algorithm->getAgreementKey($content_encryption_algorithm->getCEKSize(), $content_encryption_algorithm->getAlgorithmName(), $jwe->getRecipient(0)->getRecipientKey(), $complete_headers, $additional_headers); |
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case KeyEncryptionInterface::MODE_DIRECT: |
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Assertion::eq(1, $jwe->countRecipients(), 'Unable to encrypt for multiple recipients using key agreement algorithms.'); |
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Assertion::eq($jwe->getRecipient(0)->getRecipientKey()->get('kty'), 'oct', 'Wrong key type.'); |
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Assertion::true($jwe->getRecipient(0)->getRecipientKey()->has('k'), 'The key parameter "k" is missing.'); |
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return Base64Url::decode($jwe->getRecipient(0)->getRecipientKey()->get('k')); |
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default: |
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throw new \InvalidArgumentException(sprintf('Unsupported key management mode "%s".', $key_management_mode)); |
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} |
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} |
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/** |
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* @param \Jose\Object\JWEInterface $jwe |
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* |
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* @return string |
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*/ |
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private function getKeyManagementMode(JWEInterface $jwe) |
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{ |
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$mode = null; |
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$recipients = $jwe->getRecipients(); |
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foreach ($recipients as $recipient) { |
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$complete_headers = array_merge($jwe->getSharedProtectedHeaders(), $jwe->getSharedHeaders(), $recipient->getHeaders()); |
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Assertion::keyExists($complete_headers, 'alg', 'Parameter "alg" is missing.'); |
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$key_encryption_algorithm = $this->getJWAManager()->getAlgorithm($complete_headers['alg']); |
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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'])); |
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if (null === $mode) { |
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$mode = $key_encryption_algorithm->getKeyManagementMode(); |
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} else { |
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Assertion::true($this->areKeyManagementModesCompatible($mode, $key_encryption_algorithm->getKeyManagementMode()), 'Foreign key management mode forbidden.'); |
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} |
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} |
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return $mode; |
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} |
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/** |
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* @param \Jose\Object\JWEInterface $jwe |
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* |
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* @return \Jose\Compression\CompressionInterface|null |
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*/ |
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private function getCompressionMethod(JWEInterface $jwe) |
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{ |
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$method = null; |
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$nb_recipients = $jwe->countRecipients(); |
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for ($i = 0; $i < $nb_recipients; $i++) { |
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$complete_headers = array_merge($jwe->getSharedProtectedHeaders(), $jwe->getSharedHeaders(), $jwe->getRecipient($i)->getHeaders()); |
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if (array_key_exists('zip', $complete_headers)) { |
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if (null === $method) { |
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if (0 === $i) { |
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$method = $complete_headers['zip']; |
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} else { |
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throw new \InvalidArgumentException('Inconsistent "zip" parameter.'); |
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} |
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} else { |
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Assertion::eq($method, $complete_headers['zip'], 'Inconsistent "zip" parameter.'); |
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} |
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} else { |
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Assertion::eq(null, $method, 'Inconsistent "zip" parameter.'); |
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} |
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} |
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if (null === $method) { |
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return; |
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} |
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$compression_method = $this->getCompressionManager()->getCompressionAlgorithm($method); |
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Assertion::isInstanceOf($compression_method, CompressionInterface::class, sprintf('Compression method "%s" not supported.', $method)); |
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return $compression_method; |
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} |
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/** |
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* @param \Jose\Object\JWEInterface $jwe |
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* |
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* @return \Jose\Algorithm\ContentEncryptionAlgorithmInterface |
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*/ |
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private function getContentEncryptionAlgorithm(JWEInterface $jwe) |
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{ |
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$algorithm = null; |
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foreach ($jwe->getRecipients() as $recipient) { |
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$complete_headers = array_merge($jwe->getSharedProtectedHeaders(), $jwe->getSharedHeaders(), $recipient->getHeaders()); |
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Assertion::keyExists($complete_headers, 'enc', 'Parameter "enc" is missing.'); |
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if (null === $algorithm) { |
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$algorithm = $complete_headers['enc']; |
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} else { |
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Assertion::eq($algorithm, $complete_headers['enc'], 'Foreign content encryption algorithms are not allowed.'); |
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} |
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} |
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$content_encryption_algorithm = $this->getJWAManager()->getAlgorithm($algorithm); |
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Assertion::isInstanceOf($content_encryption_algorithm, ContentEncryptionAlgorithmInterface::class, sprintf('The content encryption algorithm "%s" is not supported or not a content encryption algorithm instance.', $algorithm)); |
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return $content_encryption_algorithm; |
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} |
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/** |
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* @param \Jose\Object\JWEInterface $jwe |
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* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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* @param string $cek |
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* @param string $iv |
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* @param \Jose\Compression\CompressionInterface|null $compression_method |
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*/ |
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private function encryptJWE(JWEInterface &$jwe, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, $cek, $iv, CompressionInterface $compression_method = null) |
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{ |
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if (!empty($jwe->getSharedProtectedHeaders())) { |
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$jwe = $jwe->withEncodedSharedProtectedHeaders(Base64Url::encode(json_encode($jwe->getSharedProtectedHeaders()))); |
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} |
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$tag = null; |
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$payload = $this->preparePayload($jwe->getPayload(), $compression_method); |
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$aad = null === $jwe->getAAD() ? null : Base64Url::encode($jwe->getAAD()); |
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$ciphertext = $content_encryption_algorithm->encryptContent($payload, $cek, $iv, $aad, $jwe->getEncodedSharedProtectedHeaders(), $tag); |
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$jwe = $jwe->withCiphertext($ciphertext); |
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$jwe = $jwe->withIV($iv); |
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if (null !== $tag) { |
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$jwe = $jwe->withTag($tag); |
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} |
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} |
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/** |
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* @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface $key_encryption_algorithm |
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* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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* @param \Jose\Object\JWKInterface $recipient_key |
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*/ |
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private function checkKeys(KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, JWKInterface $recipient_key) |
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{ |
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$this->checkKeyUsage($recipient_key, 'encryption'); |
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if ('dir' !== $key_encryption_algorithm->getAlgorithmName()) { |
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$this->checkKeyAlgorithm($recipient_key, $key_encryption_algorithm->getAlgorithmName()); |
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} else { |
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$this->checkKeyAlgorithm($recipient_key, $content_encryption_algorithm->getAlgorithmName()); |
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} |
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} |
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/** |
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* @param string $current |
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* @param string $new |
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* |
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* @return bool |
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*/ |
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private function areKeyManagementModesCompatible($current, $new) |
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{ |
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$agree = KeyEncryptionAlgorithmInterface::MODE_AGREEMENT; |
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$dir = KeyEncryptionAlgorithmInterface::MODE_DIRECT; |
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$enc = KeyEncryptionAlgorithmInterface::MODE_ENCRYPT; |
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$wrap = KeyEncryptionAlgorithmInterface::MODE_WRAP; |
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$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,]; |
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if (array_key_exists($current.$new, $supported_key_management_mode_combinations)) { |
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return $supported_key_management_mode_combinations[$current.$new]; |
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} |
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return false; |
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} |
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/** |
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* @param string $payload |
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* @param \Jose\Compression\CompressionInterface|null $compression_method |
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* |
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* @return string |
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*/ |
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private function preparePayload($payload, CompressionInterface $compression_method = null) |
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{ |
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$prepared = is_string($payload) ? $payload : json_encode($payload); |
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Assertion::notNull($prepared, 'The payload is empty or cannot encoded into JSON.'); |
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if (null === $compression_method) { |
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return $prepared; |
315
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} |
316
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$compressed_payload = $compression_method->compress($prepared); |
317
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|
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Assertion::string($compressed_payload, 'Compression failed.'); |
318
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|
319
|
|
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return $compressed_payload; |
320
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|
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} |
321
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|
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322
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/** |
323
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* @param array $complete_headers |
324
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* @param string $cek |
325
|
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* @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface $key_encryption_algorithm |
326
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|
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* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
327
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* @param \Jose\Object\JWKInterface $recipient_key |
328
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* @param array $additional_headers |
329
|
|
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* |
330
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* @return string|null |
331
|
|
|
*/ |
332
|
|
|
private function getEncryptedKey(array $complete_headers, $cek, KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key) |
333
|
|
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{ |
334
|
|
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if ($key_encryption_algorithm instanceof KeyEncryptionInterface) { |
335
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return $this->getEncryptedKeyFromKeyEncryptionAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $recipient_key, $additional_headers); |
336
|
|
|
} elseif ($key_encryption_algorithm instanceof KeyWrappingInterface) { |
337
|
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|
return $this->getEncryptedKeyFromKeyWrappingAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $recipient_key, $additional_headers); |
338
|
|
|
} elseif ($key_encryption_algorithm instanceof KeyAgreementWrappingInterface) { |
339
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return $this->getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm($complete_headers, $cek, $key_encryption_algorithm, $content_encryption_algorithm, $additional_headers, $recipient_key); |
340
|
|
|
} |
341
|
|
|
} |
342
|
|
|
|
343
|
|
|
/** |
344
|
|
|
* @param array $complete_headers |
345
|
|
|
* @param string $cek |
346
|
|
|
* @param \Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface $key_encryption_algorithm |
347
|
|
|
* @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
348
|
|
|
* @param array $additional_headers |
349
|
|
|
* @param \Jose\Object\JWKInterface $recipient_key |
350
|
|
|
* |
351
|
|
|
* @return string |
352
|
|
|
*/ |
353
|
|
|
private function getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm(array $complete_headers, $cek, KeyAgreementWrappingInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key) |
354
|
|
|
{ |
355
|
|
|
$jwt_cek = $key_encryption_algorithm->wrapAgreementKey($recipient_key, $cek, $content_encryption_algorithm->getCEKSize(), $complete_headers, $additional_headers); |
356
|
|
|
|
357
|
|
|
return $jwt_cek; |
358
|
|
|
} |
359
|
|
|
|
360
|
|
|
/** |
361
|
|
|
* @param array $complete_headers |
362
|
|
|
* @param string $cek |
363
|
|
|
* @param \Jose\Algorithm\KeyEncryption\KeyEncryptionInterface $key_encryption_algorithm |
364
|
|
|
* @param \Jose\Object\JWKInterface $recipient_key |
365
|
|
|
* @param array $additional_headers |
366
|
|
|
* |
367
|
|
|
* @return string |
368
|
|
|
*/ |
369
|
|
|
private function getEncryptedKeyFromKeyEncryptionAlgorithm(array $complete_headers, $cek, KeyEncryptionInterface $key_encryption_algorithm, JWKInterface $recipient_key, array &$additional_headers) |
370
|
|
|
{ |
371
|
|
|
return $key_encryption_algorithm->encryptKey($recipient_key, $cek, $complete_headers, $additional_headers); |
372
|
|
|
} |
373
|
|
|
|
374
|
|
|
/** |
375
|
|
|
* @param array $complete_headers |
376
|
|
|
* @param string $cek |
377
|
|
|
* @param \Jose\Algorithm\KeyEncryption\KeyWrappingInterface $key_encryption_algorithm |
378
|
|
|
* @param \Jose\Object\JWKInterface $recipient_key |
379
|
|
|
* @param array $additional_headers |
380
|
|
|
* |
381
|
|
|
* @return string |
382
|
|
|
*/ |
383
|
|
|
private function getEncryptedKeyFromKeyWrappingAlgorithm(array $complete_headers, $cek, KeyWrappingInterface $key_encryption_algorithm, JWKInterface $recipient_key, &$additional_headers) |
384
|
|
|
{ |
385
|
|
|
return $key_encryption_algorithm->wrapKey($recipient_key, $cek, $complete_headers, $additional_headers); |
386
|
|
|
} |
387
|
|
|
|
388
|
|
|
/** |
389
|
|
|
* @param array $complete_headers |
390
|
|
|
* |
391
|
|
|
* @return \Jose\Algorithm\KeyEncryptionAlgorithmInterface |
392
|
|
|
*/ |
393
|
|
|
private function findKeyEncryptionAlgorithm(array $complete_headers) |
394
|
|
|
{ |
395
|
|
|
Assertion::keyExists($complete_headers, 'alg', 'Parameter "alg" is missing.'); |
396
|
|
|
$key_encryption_algorithm = $this->getJWAManager()->getAlgorithm($complete_headers['alg']); |
397
|
|
|
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'])); |
398
|
|
|
|
399
|
|
|
return $key_encryption_algorithm; |
400
|
|
|
} |
401
|
|
|
|
402
|
|
|
/** |
403
|
|
|
* @param int $size |
404
|
|
|
* |
405
|
|
|
* @return string |
406
|
|
|
*/ |
407
|
|
|
private function createCEK($size) |
408
|
|
|
{ |
409
|
|
|
return random_bytes($size / 8); |
410
|
|
|
} |
411
|
|
|
|
412
|
|
|
/** |
413
|
|
|
* @param int $size |
414
|
|
|
* |
415
|
|
|
* @return string |
416
|
|
|
*/ |
417
|
|
|
private function createIV($size) |
418
|
|
|
{ |
419
|
|
|
return random_bytes($size / 8); |
420
|
|
|
} |
421
|
|
|
} |
422
|
|
|
|
Unless you are absolutely sure that the expression can never be null because of other conditions, we strongly recommend to add an additional type check to your code: