Complex classes like Encrypter often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Encrypter, and based on these observations, apply Extract Interface, too.
1 | <?php |
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33 | final class Encrypter implements EncrypterInterface |
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34 | { |
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35 | use HasKeyChecker; |
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36 | use HasJWAManager; |
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37 | use HasCompressionManager; |
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38 | use CommonCipheringMethods; |
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39 | |||
40 | /** |
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41 | * {@inheritdoc} |
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42 | */ |
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43 | public static function createEncrypter(array $key_encryption_algorithms, array $content_encryption_algorithms, array $compression_methods = ['DEF', 'ZLIB', 'GZ']) |
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49 | |||
50 | /** |
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51 | * Decrypter constructor. |
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52 | * |
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53 | * @param string[]|\Jose\Algorithm\KeyEncryptionAlgorithmInterface[] $key_encryption_algorithms |
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54 | * @param string[]|\Jose\Algorithm\ContentEncryptionAlgorithmInterface[] $content_encryption_algorithms |
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55 | * @param string[]|\Jose\Compression\CompressionInterface[] $compression_methods |
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56 | */ |
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57 | public function __construct(array $key_encryption_algorithms, array $content_encryption_algorithms, array $compression_methods) |
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65 | |||
66 | /** |
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67 | * {@inheritdoc} |
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68 | */ |
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69 | public function encrypt(JWEInterface &$jwe) |
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95 | |||
96 | /** |
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97 | * @param \Jose\Object\JWEInterface $jwe |
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98 | * @param \Jose\Object\RecipientInterface $recipient |
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99 | * @param string $cek |
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100 | * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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101 | * @param array $additional_headers |
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102 | */ |
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103 | private function processRecipient(JWEInterface $jwe, RecipientInterface &$recipient, $cek, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers) |
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120 | |||
121 | /** |
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122 | * @param \Jose\Object\JWEInterface $jwe |
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123 | * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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124 | * @param string $key_management_mode |
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125 | * @param array $additional_headers |
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126 | * |
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127 | * @return string |
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128 | */ |
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129 | private function determineCEK(JWEInterface $jwe, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, $key_management_mode, array &$additional_headers) |
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151 | |||
152 | /** |
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153 | * @param \Jose\Object\JWEInterface $jwe |
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154 | * |
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155 | * @return string |
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156 | */ |
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157 | private function getKeyManagementMode(JWEInterface $jwe) |
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178 | |||
179 | /** |
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180 | * @param \Jose\Object\JWEInterface $jwe |
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181 | * |
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182 | * @return \Jose\Compression\CompressionInterface|null |
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183 | */ |
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184 | private function getCompressionMethod(JWEInterface $jwe) |
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215 | |||
216 | /** |
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217 | * @param \Jose\Object\JWEInterface $jwe |
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218 | * |
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219 | * @return \Jose\Algorithm\ContentEncryptionAlgorithmInterface |
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220 | */ |
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221 | private function getContentEncryptionAlgorithm(JWEInterface $jwe) |
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240 | |||
241 | /** |
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242 | * @param \Jose\Object\JWEInterface $jwe |
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243 | * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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244 | * @param string $cek |
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245 | * @param string $iv |
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246 | * @param \Jose\Compression\CompressionInterface|null $compression_method |
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247 | */ |
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248 | private function encryptJWE(JWEInterface &$jwe, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, $cek, $iv, CompressionInterface $compression_method = null) |
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265 | |||
266 | /** |
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267 | * @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface $key_encryption_algorithm |
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268 | * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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269 | * @param \Jose\Object\JWKInterface $recipient_key |
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270 | */ |
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271 | private function checkKeys(KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, JWKInterface $recipient_key) |
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280 | |||
281 | /** |
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282 | * @param string $current |
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283 | * @param string $new |
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284 | * |
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285 | * @return bool |
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286 | */ |
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287 | private function areKeyManagementModesCompatible($current, $new) |
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301 | |||
302 | /** |
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303 | * @param string $payload |
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304 | * @param \Jose\Compression\CompressionInterface|null $compression_method |
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305 | * |
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306 | * @return string |
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307 | */ |
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308 | private function preparePayload($payload, CompressionInterface $compression_method = null) |
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321 | |||
322 | /** |
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323 | * @param array $complete_headers |
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324 | * @param string $cek |
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325 | * @param \Jose\Algorithm\KeyEncryptionAlgorithmInterface $key_encryption_algorithm |
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326 | * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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327 | * @param \Jose\Object\JWKInterface $recipient_key |
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328 | * @param array $additional_headers |
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329 | * |
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330 | * @return string|null |
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331 | */ |
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332 | private function getEncryptedKey(array $complete_headers, $cek, KeyEncryptionAlgorithmInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key) |
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342 | |||
343 | /** |
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344 | * @param array $complete_headers |
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345 | * @param string $cek |
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346 | * @param \Jose\Algorithm\KeyEncryption\KeyAgreementWrappingInterface $key_encryption_algorithm |
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347 | * @param \Jose\Algorithm\ContentEncryptionAlgorithmInterface $content_encryption_algorithm |
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348 | * @param array $additional_headers |
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349 | * @param \Jose\Object\JWKInterface $recipient_key |
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350 | * |
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351 | * @return string |
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352 | */ |
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353 | private function getEncryptedKeyFromKeyAgreementAndKeyWrappingAlgorithm(array $complete_headers, $cek, KeyAgreementWrappingInterface $key_encryption_algorithm, ContentEncryptionAlgorithmInterface $content_encryption_algorithm, array &$additional_headers, JWKInterface $recipient_key) |
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359 | |||
360 | /** |
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361 | * @param array $complete_headers |
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362 | * @param string $cek |
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363 | * @param \Jose\Algorithm\KeyEncryption\KeyEncryptionInterface $key_encryption_algorithm |
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364 | * @param \Jose\Object\JWKInterface $recipient_key |
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365 | * @param array $additional_headers |
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366 | * |
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367 | * @return string |
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368 | */ |
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369 | private function getEncryptedKeyFromKeyEncryptionAlgorithm(array $complete_headers, $cek, KeyEncryptionInterface $key_encryption_algorithm, JWKInterface $recipient_key, array &$additional_headers) |
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373 | |||
374 | /** |
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375 | * @param array $complete_headers |
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376 | * @param string $cek |
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377 | * @param \Jose\Algorithm\KeyEncryption\KeyWrappingInterface $key_encryption_algorithm |
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378 | * @param \Jose\Object\JWKInterface $recipient_key |
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379 | * @param array $additional_headers |
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380 | * |
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381 | * @return string |
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382 | */ |
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383 | private function getEncryptedKeyFromKeyWrappingAlgorithm(array $complete_headers, $cek, KeyWrappingInterface $key_encryption_algorithm, JWKInterface $recipient_key, &$additional_headers) |
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387 | |||
388 | /** |
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389 | * @param array $complete_headers |
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390 | * |
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391 | * @return \Jose\Algorithm\KeyEncryptionAlgorithmInterface |
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392 | */ |
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393 | private function findKeyEncryptionAlgorithm(array $complete_headers) |
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401 | |||
402 | /** |
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403 | * @param int $size |
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404 | * |
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405 | * @return string |
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406 | */ |
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407 | private function createCEK($size) |
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411 | |||
412 | /** |
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413 | * @param int $size |
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414 | * |
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415 | * @return string |
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416 | */ |
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417 | private function createIV($size) |
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421 | } |
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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: