Completed
Push — master ( e884a0...7997b7 )
by Neomerx
05:34
created

SymmetricCryptSettings::getSettings()   A

Complexity

Conditions 1
Paths 1

Size

Total Lines 10
Code Lines 7

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 6
CRAP Score 1

Importance

Changes 0
Metric Value
dl 0
loc 10
ccs 6
cts 6
cp 1
rs 9.4285
c 0
b 0
f 0
cc 1
eloc 7
nc 1
nop 0
crap 1
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<?php namespace Limoncello\Crypt\Package;
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/**
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 * Copyright 2015-2017 [email protected]
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 * http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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use Limoncello\Contracts\Settings\SettingsInterface;
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/**
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 * @package Limoncello\Crypt
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 */
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class SymmetricCryptSettings implements SettingsInterface
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{
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    /** Default crypt method */
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    const DEFAULT_METHOD = 'aes-256-ctr';
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    /** Default Initialization Vector (IV) */
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    const DEFAULT_IV = '';
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    /**
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     * Encryption method to be used. For a list of available methods on your machine see openssl_get_cipher_methods().
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     *
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     * @see http://php.net/manual/en/function.openssl-get-cipher-methods.php
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     */
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    const KEY_METHOD = 0;
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    /** Settings key */
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    const KEY_PASSWORD = self::KEY_METHOD + 1;
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    /** Settings key */
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    const KEY_IV = self::KEY_PASSWORD + 1;
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    /**
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     * @see http://php.net/manual/en/function.openssl-encrypt.php OPENSSL_ZERO_PADDING
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     *
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     * From @link http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38a.pdf
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     * Appendix A: Padding
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     * ~~~~~~~~~~~~~~~~~~~
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     * For the ECB, CBC, and CFB modes, the plaintext must be a sequence of one or more complete
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     * data blocks (or, for CFB mode, data segments). In other words, for these three modes, the total
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     * number of bits in the plaintext must be a positive multiple of the block (or segment) size.
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     * If the data string to be encrypted does not initially satisfy this property, then the formatting of the
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     * plaintext must entail an increase in the number of bits. A common way to achieve the necessary
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     * increase is to append some extra bits, called padding, to the trailing end of the data string as the
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     * last step in the formatting of the plaintext. An example of a padding method is to append a
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     * single ‘1’ bit to the data string and then to pad the resulting string by as few ‘0’ bits, possibly
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     * none, as are necessary to complete the final block (segment). Other methods may be used; in
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     * general, the formatting of the plaintext is outside the scope of this recommendation.
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     * For the above padding method, the padding bits can be removed unambiguously, provided the
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     * receiver can determine that the message is indeed padded. One way to ensure that the receiver
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     * does not mistakenly remove bits from an unpadded message is to require the sender to pad every
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     * message, including messages in which the final block (segment) is already complete. For such
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     * messages, an entire block (segment) of padding is appended. Alternatively, such messages can
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     * be sent without padding if, for every message, the existence of padding can be reliably inferred,
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     * e.g., from a message length indicator.
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     */
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    const KEY_USE_ZERO_PADDING = self::KEY_IV + 1;
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    // Authenticated Encryption with Associated Data specific keys (since PHP 7.1)
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    // @link http://php.net/manual/en/function.openssl-encrypt.php
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    /** Settings key */
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    const KEY_USE_AUTHENTICATION = self::KEY_USE_ZERO_PADDING + 1;
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    /** Settings key */
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    const KEY_TAG_LENGTH = self::KEY_USE_AUTHENTICATION + 1;
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    /** Settings key */
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    const KEY_LAST = self::KEY_TAG_LENGTH;
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    /**
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     * @inheritdoc
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     */
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    final public function get(): array
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    {
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        $defaults = $this->getSettings();
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        $password = $defaults[static::KEY_PASSWORD] ?? null;
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        assert(empty($password) === false, "Password cannot be empty.");
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        return $defaults;
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    }
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    /**
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     * @return array
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     */
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    protected function getSettings(): array
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    {
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        return [
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            static::KEY_METHOD             => static::DEFAULT_METHOD,
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            static::KEY_IV                 => static::DEFAULT_IV,
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            static::KEY_USE_ZERO_PADDING   => false,
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            static::KEY_USE_AUTHENTICATION => false,
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            static::KEY_TAG_LENGTH         => 16,
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        ];
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    }
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}
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