array( 'cbc' => 'cbc', 'ecb' => 'ecb', 'ofb' => 'nofb', 'ofb8' => 'ofb', 'cfb' => 'ncfb', 'cfb8' => 'cfb', 'ctr' => 'ctr', 'stream' => 'stream' ), 'openssl' => array( 'cbc' => 'cbc', 'ecb' => 'ecb', 'ofb' => 'ofb', 'cfb' => 'cfb', 'cfb8' => 'cfb8', 'ctr' => 'ctr', 'stream' => '', 'gcm' => 'gcm', 'xts' => 'xts' ) ); /** * List of supported HMAC algorightms * * name => digest size pairs * * @var array */ protected $_digests = array( 'sha224' => 28, 'sha256' => 32, 'sha384' => 48, 'sha512' => 64 ); // -------------------------------------------------------------------- /** * Class constructor * * @param array $params Configuration parameters * @return void */ public function __construct(array $params = array()) { $this->_drivers = array( 'mcrypt' => defined('MCRYPT_DEV_URANDOM'), // While OpenSSL is available for PHP 5.3.0, an IV parameter // for the encrypt/decrypt functions is only available since 5.3.3 'openssl' => (is_php('5.3.3') && extension_loaded('openssl')) ); if ( ! $this->_drivers['mcrypt'] && ! $this->_drivers['openssl']) { return show_error('Encryption: Unable to find an available encryption driver.'); } $this->initialize($params); isset($this->_key) OR $this->_key = config_item('encryption_key'); if (empty($this->_key)) { return show_error('Encryption: You are required to set an encryption key in your configuration.'); } log_message('debug', 'Encryption Class Initialized'); } // -------------------------------------------------------------------- /** * Initialize * * @param array $params Configuration parameters * @return CI_Encryption */ public function initialize(array $params) { if ( ! empty($params['driver'])) { if (isset($this->_drivers[$params['driver']])) { if ($this->_drivers[$params['driver']]) { $this->_driver = $params['driver']; } else { log_message('error', "Encryption: Driver '".$params['driver']."' is not available."); } } else { log_message('error', "Encryption: Unknown driver '".$params['driver']."' cannot be configured."); } } if (empty($this->_driver)) { $this->_driver = ($this->_drivers['openssl'] === TRUE) ? 'openssl' : 'mcrypt'; log_message('debug', "Encryption: Auto-configured driver '".$this->_driver."'."); } empty($params['key']) OR $this->_key = $params['key']; $this->{'_'.$this->_driver.'_initialize'}($params); return $this; } // -------------------------------------------------------------------- /** * Initialize MCrypt * * @param array $params Configuration parameters * @return void */ protected function _mcrypt_initialize($params) { if ( ! empty($params['cipher'])) { $params['cipher'] = strtolower($params['cipher']); $this->_cipher_alias($params['cipher']); if ( ! in_array($params['cipher'], mcrypt_list_algorithms(), TRUE)) { log_message('error', 'Encryption: MCrypt cipher '.strtoupper($params['cipher']).' is not available.'); } else { $this->_cipher = $params['cipher']; } } if ( ! empty($params['mode'])) { $params['mode'] = strtolower($params['mode']); if ( ! isset($this->_modes['mcrypt'][$params['mode']])) { log_message('error', 'Encryption: MCrypt mode '.strtotupper($params['mode']).' is not available.'); } else { $this->_mode = $this->_modes['mcrypt'][$params['mode']]; } } if (isset($this->_cipher, $this->_mode)) { if (is_resource($this->_handle) && (strtolower(mcrypt_enc_get_algorithms_name($this->_handle)) !== $this->_cipher OR strtolower(mcrypt_enc_get_modes_name($this->_handle)) !== $this->_mode) ) { mcrypt_module_close($this->_handle); } if ($this->_handle = mcrypt_module_open($this->_cipher, '', $this->_mode, '')) { log_message('debug', 'Encryption: MCrypt cipher '.strtoupper($this->_cipher).' initialized in '.strtoupper($this->_mode).' mode.'); } else { log_message('error', 'Encryption: Unable to initialize MCrypt with cipher '.strtoupper($this->_cipher).' in '.strtoupper($this->_mode).' mode.'); } } } // -------------------------------------------------------------------- /** * Initialize OpenSSL * * @param array $params Configuration parameters * @return void */ protected function _openssl_initialize($params) { if ( ! empty($params['cipher'])) { $params['cipher'] = strtolower($params['cipher']); $this->_cipher_alias($params['cipher']); $this->_cipher = $params['cipher']; } if ( ! empty($params['mode'])) { $params['mode'] = strtolower($params['mode']); if ( ! isset($this->_modes['openssl'][$params['mode']])) { log_message('error', 'Encryption: OpenSSL mode '.strtotupper($params['mode']).' is not available.'); } else { $this->_mode = $this->_modes['openssl'][$params['mode']]; } } if (isset($this->_cipher, $this->_mode)) { // This is mostly for the stream mode, which doesn't get suffixed in OpenSSL $handle = empty($this->_mode) ? $this->_cipher : $this->_cipher.'-'.$this->_mode; if ( ! in_array($handle, openssl_get_cipher_methods(), TRUE)) { $this->_handle = NULL; log_message('error', 'Encryption: Unable to initialize OpenSSL with method '.strtoupper($handle).'.'); } else { $this->_handle = $handle; log_message('debug', 'Encryption: OpenSSL initialized with method '.strtoupper($handle).'.'); } } } // -------------------------------------------------------------------- /** * Encrypt * * @param string $data Input data * @param array $params Input parameters * @return string */ public function encrypt($data, array $params = NULL) { if (($params = $this->_get_params($params)) === FALSE) { return FALSE; } elseif ( ! isset($params['key'])) { if ( ! isset($this->_key)) { return show_error('Encryption: You are required to set an encryption key in your configuration.'); } $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption'); } if (($data = $this->{'_'.$this->_driver.'_encrypt'}($data, $params)) === FALSE) { return FALSE; } $params['base64'] && $data = base64_encode($data); if (isset($params['hmac_digest'])) { isset($params['hmac_key']) OR $params['hmac_key'] = $this->hkdf($this->_key, 'sha512', NULL, NULL, 'authentication'); return hash_hmac($params['hmac_digest'], $data, $params['hmac_key'], ! $params['base64']).$data; } return $data; } // -------------------------------------------------------------------- /** * Encrypt via MCrypt * * @param string $data Input data * @param array $params Input parameters * @return string */ protected function _mcrypt_encrypt($data, $params) { if ( ! is_resource($params['handle'])) { return FALSE; } elseif ( ! isset($params['iv'])) { // The greater-than-1 comparison is mostly a work-around for a bug, // where 1 is returned for ARCFour instead of 0. $params['iv'] = (($iv_size = mcrypt_enc_get_iv_size($params['handle'])) > 1) ? mcrypt_create_iv($iv_size, MCRYPT_DEV_URANDOM) : NULL; } // CAST-128 compatibility (http://tools.ietf.org/rfc/rfc2144.txt) // // RFC2144 says that keys shorter than 16 bytes are to be padded with // zero bytes to 16 bytes, but (surprise) MCrypt doesn't do that. if ($params['cipher'] === 'cast-128' && ($kl = strlen($params['key'])) < 16) { $params['key'] .= str_repeat("\x0", 16 - $kl); } if (mcrypt_generic_init($params['handle'], $params['key'], $params['iv']) < 0) { if ($params['handle'] !== $this->_handle) { mcrypt_module_close($params['handle']); } return FALSE; } // Use PKCS#7 padding in order to ensure compatibility with OpenSSL // and other implementations outside of PHP. if (in_array(strtolower(mcrypt_enc_get_modes_name($params['handle'])), array('cbc', 'ecb'), TRUE)) { $block_size = mcrypt_enc_get_block_size($params['handle']); $pad = $block_size - (strlen($data) % $block_size); $data .= str_repeat(chr($pad), $pad); } // Work-around for yet another strange behavior in MCrypt. // // When encrypting in ECB mode, the IV is ignored. Yet // mcrypt_enc_get_iv_size() returns a value larger than 0 // even if ECB is used AND mcrypt_generic_init() complains // if you don't pass an IV with length equal to the said // return value. // // This probably would've been fine (even though still wasteful), // but OpenSSL isn't that dumb and we need to make the process // portable, so ... $data = (mcrypt_enc_get_modes_name($params['handle']) !== 'ECB') ? $params['iv'].mcrypt_generic($params['handle'], $data) : mcrypt_generic($params['handle'], $data); mcrypt_generic_deinit($params['handle']); if ($params['handle'] !== $this->_handle) { mcrypt_module_close($params['handle']); } return $data; } // -------------------------------------------------------------------- /** * Encrypt via OpenSSL * * @param string $data Input data * @param array $params Input parameters * @return string */ protected function _openssl_encrypt($data, $params) { if (empty($params['handle'])) { return FALSE; } elseif ( ! isset($params['iv'])) { $params['iv'] = ($iv_size = openssl_cipher_iv_length($params['handle'])) ? openssl_random_pseudo_bytes($iv_size) : NULL; } $data = openssl_encrypt( $data, $params['handle'], $params['key'], 1, // DO NOT TOUCH! $params['iv'] ); if ($data === FALSE) { return FALSE; } return $params['iv'].$data; } // -------------------------------------------------------------------- /** * Decrypt * * @param string $data Encrypted data * @param array $params Input parameters * @return string */ public function decrypt($data, array $params = NULL) { if (($params = $this->_get_params($params)) === FALSE) { return FALSE; } elseif ( ! isset($params['key'])) { if ( ! isset($this->_key)) { return show_error('Encryption: You are required to set an encryption key in your configuration.'); } $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption'); } if (isset($params['hmac_digest'])) { // This might look illogical, but it is done during encryption as well ... // The 'base64' value is effectively an inverted "raw data" parameter $digest_size = ($params['base64']) ? $this->_digests[$params['hmac_digest']] * 2 : $this->_digests[$params['hmac_digest']]; if (strlen($data) <= $digest_size) { return FALSE; } $hmac_input = substr($data, 0, $digest_size); $data = substr($data, $digest_size); isset($params['hmac_key']) OR $params['hmac_key'] = $this->hkdf($this->_key, 'sha512', NULL, NULL, 'authentication'); $hmac_check = hash_hmac($params['hmac_digest'], $data, $params['hmac_key'], ! $params['base64']); // Time-attack-safe comparison $diff = 0; for ($i = 0; $i < $digest_size; $i++) { $diff |= ord($hmac_input[$i]) ^ ord($hmac_check[$i]); } if ($diff !== 0) { return FALSE; } } if ($params['base64']) { $data = base64_decode($data); } if (isset($params['iv']) && strncmp($params['iv'], $data, $iv_size = strlen($params['iv'])) === 0) { $data = substr($data, $iv_size); } return $this->{'_'.$this->_driver.'_decrypt'}($data, $params); } // -------------------------------------------------------------------- /** * Decrypt via MCrypt * * @param string $data Encrypted data * @param array $params Input parameters * @return string */ protected function _mcrypt_decrypt($data, $params) { if ( ! is_resource($params['handle'])) { return FALSE; } elseif ( ! isset($params['iv'])) { // The greater-than-1 comparison is mostly a work-around for a bug, // where 1 is returned for ARCFour instead of 0. if (($iv_size = mcrypt_enc_get_iv_size($params['handle'])) > 1) { if (mcrypt_enc_get_modes_name($params['handle']) !== 'ECB') { $params['iv'] = substr($data, 0, $iv_size); $data = substr($data, $iv_size); } else { // MCrypt is dumb and this is ignored, only size matters $params['iv'] = str_repeat("\x0", $iv_size); } } else { $params['iv'] = NULL; } } // CAST-128 compatibility (http://tools.ietf.org/rfc/rfc2144.txt) // // RFC2144 says that keys shorter than 16 bytes are to be padded with // zero bytes to 16 bytes, but (surprise) MCrypt doesn't do that. if ($params['cipher'] === 'cast-128' && ($kl = strlen($params['key'])) < 16) { $params['key'] .= str_repeat("\x0", 16 - $kl); } if (mcrypt_generic_init($params['handle'], $params['key'], $params['iv']) < 0) { if ($params['handle'] !== $this->_handle) { mcrypt_module_close($params['handle']); } return FALSE; } $data = mdecrypt_generic($params['handle'], $data); // Remove PKCS#7 padding, if necessary if (in_array(strtolower(mcrypt_enc_get_modes_name($params['handle'])), array('cbc', 'ecb'), TRUE)) { $data = substr($data, 0, -ord($data[strlen($data)-1])); } mcrypt_generic_deinit($params['handle']); if ($params['handle'] !== $this->_handle) { mcrypt_module_close($params['handle']); } return $data; } // -------------------------------------------------------------------- /** * Decrypt via OpenSSL * * @param string $data Encrypted data * @param array $params Input parameters * @return string */ protected function _openssl_decrypt($data, $params) { if ( ! isset($params['iv'])) { if ($iv_size = openssl_cipher_iv_length($params['handle'])) { $params['iv'] = substr($data, 0, $iv_size); $data = substr($data, $iv_size); } else { $params['iv'] = NULL; } } return empty($params['handle']) ? FALSE : openssl_decrypt( $data, $params['handle'], $params['key'], 1, // DO NOT TOUCH! $params['iv'] ); } // -------------------------------------------------------------------- /** * Get params * * @param array $params Input parameters * @return array */ protected function _get_params($params) { if (empty($params)) { return isset($this->_cipher, $this->_mode, $this->_key, $this->_handle) ? array( 'handle' => $this->_handle, 'cipher' => $this->_cipher, 'mode' => $this->_mode, 'key' => NULL, 'base64' => TRUE, 'hmac_digest' => ($this->_mode !== 'gcm' ? 'sha512' : NULL), 'hmac_key' => NULL ) : FALSE; } elseif ( ! isset($params['cipher'], $params['mode'], $params['key'])) { return FALSE; } if (isset($params['mode'])) { $params['mode'] = strtolower($params['mode']); if ( ! isset($this->_modes[$this->_driver][$params['mode']])) { return FALSE; } else { $params['mode'] = $this->_modes[$this->_driver][$params['mode']]; } } if ($params['mode'] === 'gcm' OR isset($params['hmac']) && $params['hmac'] === FALSE) { $params['hmac_digest'] = $params['hmac_key'] = NULL; } else { if ( ! isset($params['hmac_key'])) { return FALSE; } elseif (isset($params['hmac_digest'])) { $params['hmac_digest'] = strtolower($params['hmac_digest']); if ( ! isset($this->_digests[$params['hmac_digest']])) { return FALSE; } } else { $params['hmac_digest'] = 'sha512'; } } $params = array( 'handle' => NULL, 'cipher' => $params['cipher'], 'mode' => $params['mode'], 'key' => $params['key'], 'iv' => isset($params['iv']) ? $params['iv'] : NULL, 'base64' => isset($params['base64']) ? $params['base64'] : TRUE, 'hmac_digest' => $params['hmac_digest'], 'hmac_key' => $params['hmac_key'] ); $this->_cipher_alias($params['cipher']); $params['handle'] = ($params['cipher'] !== $this->_cipher OR $params['mode'] !== $this->_mode) ? $this->{'_'.$this->_driver.'_get_handle'}($params['cipher'], $params['mode']) : $this->_handle; return $params; } // -------------------------------------------------------------------- /** * Get MCrypt handle * * @param string $cipher Cipher name * @param string $mode Encryption mode * @return resource */ protected function _mcrypt_get_handle($cipher, $mode) { return mcrypt_module_open($cipher, '', $mode, ''); } // -------------------------------------------------------------------- /** * Get OpenSSL handle * * @param string $cipher Cipher name * @param string $mode Encryption mode * @return string */ protected function _openssl_get_handle($cipher, $mode) { // OpenSSL methods aren't suffixed with '-stream' for this mode return ($mode === 'stream') ? $cipher : $cipher.'-'.$mode; } // -------------------------------------------------------------------- /** * Cipher alias * * Tries to translate cipher names between MCrypt and OpenSSL's "dialects". * * @param string $cipher Cipher name * @return void */ protected function _cipher_alias(&$cipher) { static $dictionary; if (empty($dictionary)) { $dictionary = array( 'mcrypt' => array( 'aes-128' => 'rijndael-128', 'aes-192' => 'rijndael-128', 'aes-256' => 'rijndael-128', 'des3-ede3' => 'tripledes', 'bf' => 'blowfish', 'cast5' => 'cast-128', 'rc4' => 'arcfour', 'rc4-40' => 'arcfour' ), 'openssl' => array( 'rijndael-128' => 'aes-128', 'tripledes' => 'des-ede3', 'blowfish' => 'bf', 'cast-128' => 'cast5', 'arcfour' => 'rc4-40', 'rc4' => 'rc4-40' ) ); // Notes: // // - Rijndael-128 is, at the same time all three of AES-128, // AES-192 and AES-256. The only difference between them is // the key size. Rijndael-192, Rijndael-256 on the other hand // also have different block sizes and are NOT AES-compatible. // // - Blowfish is said to be supporting key sizes between // 4 and 56 bytes, but it appears that between MCrypt and // OpenSSL, only those of 16 and more bytes are compatible. // Also, don't know what MCrypt's 'blowfish-compat' is. // // - CAST-128/CAST5 produces a longer cipher when encrypted via // OpenSSL, but (strangely enough) can be decrypted by either // extension anyway. // Also, RFC2144 says that the cipher supports key sizes // between 5 and 16 bytes by the implementation actually // zero-padding them to 16 bytes, but MCrypt doesn't do that. // // - RC4 (ARCFour) has a strange implementation under OpenSSL. // Its 'rc4-40' cipher method seems to work flawlessly, yet // there's another one, 'rc4' that only works with a 16-byte key. // // - DES is compatible, but doesn't need an alias. // // Other seemingly matching ciphers between MCrypt, OpenSSL: // // - RC2 is NOT compatible and only an obscure forum post // confirms that it is MCrypt's fault. } if (isset($dictionary[$this->_driver][$cipher])) { $cipher = $dictionary[$this->_driver][$cipher]; } } // -------------------------------------------------------------------- /** * HKDF * * @link https://tools.ietf.org/rfc/rfc5869.txt * @param $key Input key * @param $digest A SHA-2 hashing algorithm * @param $salt Optional salt * @param $info Optional context/application-specific info * @param $length Output length (defaults to the selected digest size) * @return string A pseudo-random key */ public function hkdf($key, $digest = 'sha512', $salt = NULL, $length = NULL, $info = '') { if ( ! isset($this->_digests[$digest])) { return FALSE; } if (empty($length) OR ! is_int($length)) { $length = $this->_digests[$digest]; } elseif ($length > (255 * $this->_digests[$digest])) { return FALSE; } isset($salt) OR $salt = str_repeat("\0", $this->_digests[$digest]); $prk = hash_hmac($digest, $key, $salt, TRUE); $key = ''; for ($key_block = '', $block_index = 1; strlen($key) < $length; $block_index++) { $key_block = hash_hmac($digest, $key_block.$info.chr($block_index), $prk, TRUE); $key .= $key_block; } return substr($key, 0, $length); } // -------------------------------------------------------------------- /** * __get() magic * * @param string $key Property name * @return mixed */ public function __get($key) { return in_array($key, array('cipher', 'mode', 'driver', 'drivers', 'digests'), TRUE) ? $this->{'_'.$key} : NULL; } } /* End of file Encryption.php */ /* Location: ./system/libraries/Encryption.php */