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<?php |
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namespace Graceland\SafeInCloud; |
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class Encrypter |
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{ |
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const BLOCK_SIZE = 16; |
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const KEY_SIZE = 32; |
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protected $generator; |
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protected $key; |
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public static function generateKey() |
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{ |
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return bin2hex(openssl_random_pseudo_bytes(round(static::KEY_SIZE / 2))); |
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} |
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public function __construct($key) |
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{ |
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if (strlen($key) !== (static::KEY_SIZE)) { |
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throw new \RuntimeException('The supplied encryption key must be '.(static::KEY_SIZE).' bits'); |
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} |
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$this->key = $key; |
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} |
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/** |
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* @return string |
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*/ |
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public function decrypt($value, $nonce) |
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{ |
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$value = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $this->key, $value, MCRYPT_MODE_CBC, $nonce); |
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return $this->stripPadding($value); |
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} |
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public function encrypt($value, $nonce) |
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{ |
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$value = $this->addPadding($value); |
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return mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $this->key, $value, MCRYPT_MODE_CBC, $nonce); |
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} |
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public function generateNonce() |
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{ |
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return mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC), $this->getRandomizer()); |
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} |
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/** |
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* @return string |
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*/ |
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public function getKey() |
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{ |
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return $this->key; |
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} |
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protected function addPadding($value) |
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{ |
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$pad = static::BLOCK_SIZE - (strlen($value) % static::BLOCK_SIZE); |
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$value = $value.str_repeat(chr($pad), $pad); |
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return $value; |
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} |
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protected function getRandomizer() |
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{ |
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if (defined('MCRYPT_DEV_URANDOM')) { |
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return MCRYPT_DEV_URANDOM; |
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} |
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if (defined('MCRYPT_DEV_RANDOM')) { |
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return MCRYPT_DEV_RANDOM; |
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} |
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mt_srand(); |
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return MCRYPT_RAND; |
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} |
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protected function isPaddingValid($pad, $value) |
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{ |
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$beforePad = strlen($value) - $pad; |
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return substr($value, $beforePad) == str_repeat(substr($value, -1), $pad); |
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} |
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/** |
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* @return string |
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*/ |
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protected function stripPadding($value) |
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{ |
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$pad = ord($value[($len = strlen($value)) - 1]); |
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return $this->isPaddingValid($pad, $value) ? substr($value, 0, $len - $pad) : $value; |
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} |
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} |
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