85 lines
No EOL
3.3 KiB
PHP
85 lines
No EOL
3.3 KiB
PHP
<?php
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/**
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* Basic encryption/decryption class.
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* We use this class atm for encrypting & decrypting the imap passwords.
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*/
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class MyCrypt{
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private $config; /**< array that should contain the enc_method & hash_method & key */
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/**
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* constructor.
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* loads the config array with the given argument.
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* @param $cryptinfo an array containing the info needed to encrypt & decrypt.(enc_method & hash_method & key)
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*/
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function __construct($cryptinfo) {
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$this->config = $cryptinfo;
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}
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/**
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* encrypts by using the given enc_method and hash_method.
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* It will first check if the methods are supported, if not it will throw an error, if so it will encrypt the $data
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* @param $data the string that we want to encrypt.
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* @return the encrypted string.
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*/
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public function encrypt($data) {
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self::check_methods($this->config['enc_method'], $this->config['hash_method']);
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$iv = self::hashIV($this->config['key'], $this->config['hash_method'], openssl_cipher_iv_length($this->config['enc_method']));
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$infostr = sprintf('$%s$%s$', $this->config['enc_method'], $this->config['hash_method']);
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return $infostr . openssl_encrypt($data, $this->config['enc_method'], $this->config['key'], false, $iv);
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}
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/**
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* decrypts by using the given enc_method and hash_method.
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* @param $edata the encrypted string that we want to decrypt
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* @return the decrypted string.
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*/
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public function decrypt($edata) {
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$e_arr = explode('$', $edata);
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if( count($e_arr) != 4 ) {
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Throw new Exception('Given data is missing crucial sections.');
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}
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$this->config['enc_method'] = $e_arr[1];
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$this->config['hash_method'] = $e_arr[2];
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self::check_methods($this->config['enc_method'], $this->config['hash_method']);
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$iv = self::hashIV($this->config['key'], $this->config['hash_method'], openssl_cipher_iv_length($this->config['enc_method']));
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return openssl_decrypt($e_arr[3], $this->config['enc_method'], $this->config['key'], false, $iv);
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}
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/**
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* hashes the key by using a hash method specified.
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* @param $key the key to be hashed
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* @param $method the metho of hashing to be used
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* @param $iv_size the size of the initialization vector.
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* @return return the hashed key up till the size of the iv_size param.
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*/
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private static function hashIV($key, $method, $iv_size) {
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$myhash = hash($method, $key, TRUE);
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while( strlen($myhash) < $iv_size ) {
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$myhash .= hash($method, $myhash, TRUE);
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}
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return substr($myhash, 0, $iv_size);
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}
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/**
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* checks if the encryption and hash methods are supported
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* @param $enc the encryption method.
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* @param $hash the hash method.
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* @throw Exception in case a method is not supported.
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*/
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private static function check_methods($enc, $hash) {
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if( ! function_exists('openssl_encrypt') ) {
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Throw new Exception('openssl_encrypt() not supported.');
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} else if( ! in_array($enc, openssl_get_cipher_methods()) ) {
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Throw new Exception('Encryption method ' . $enc . ' not supported.');
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} else if( ! in_array(strtolower($hash), hash_algos()) ) {
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Throw new Exception('Hashing method ' . $hash . ' not supported.');
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}
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}
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} |