/src/PortePlugins/Crypt.php

<?php

/**
 * Copyright (c) 2008, SARL Adaltas. All rights reserved.
 * Code licensed under the BSD License:
 * http://www.php-pop.org/porte/license.html
 */

/**
 * Plugin to store crypted content into the database.
 * 
 * @author     David Worms info(at)adaltas.com
 * @copyright  2008-2009 Adaltas
 */
class PortePlugins_Crypt{
	
	public static $methods = array('AES'=>array('ECB'));
	
	/**
	 * Register the plugin with a Porte instance.
	 */
	public static function register(Porte $porte){
		PorteEvents::connect('model_property_before',array('PortePlugins_Crypt','_modelPropertyBefore'));
	}
	
	public static function _modelPropertyBefore($models,$type,$property){
		$model = $models->{$type};
		$propertyModel = $model['properties'][$property];
		if(!empty($propertyModel['crypt'])){
			switch(gettype($propertyModel['crypt'])){
				case 'boolean';
				case 'integer';
					$propertyModel['crypt'] = array(
						'method' => 'AES');
					break;
				case 'string';
					$propertyModel['crypt'] = array(
						'method' => 'AES',
						'key'=>$propertyModel['crypt']);
					break;
				case 'array':
					// ok
					break;
				default:
					throw new PorteException('Invalid AES configuration "'.$type.'.'.$property.'": "'.PurLang::toString($propertyModel).'"');
			}
			if(!empty($models->config->crypt)){
				$propertyModel['crypt'] = array_merge($models->config->crypt,$propertyModel['crypt']);
			}else if(!empty($model['crypt'])){
				$propertyModel['crypt'] = array_merge($model['crypt'],$propertyModel['crypt']);
			}
			if(empty($propertyModel['crypt']['hex'])){
				$propertyModel['crypt']['hex'] = false;
			}
			if(array_key_exists('method',$propertyModel['crypt'])&&empty($propertyModel['crypt']['method'])){
				// it's ok, if method is defined but null or empty,
				// we only convert the value to hexadecimal
				$propertyModel['crypt']['method'] = null;
			}else if(empty($propertyModel['crypt']['method'])){
				$propertyModel['crypt']['method'] = 'AES';
			}else{
				$propertyModel['crypt']['method'] = strtoupper($propertyModel['crypt']['method']);
				if(!in_array($propertyModel['crypt']['method'],array_keys(self::$methods))){
					throw new PorteException('Incryption method not supported in "'.$type.'.'.$property.'": "'.$propertyModel['crypt']['method'].'"'); 
				}
			}
			if($propertyModel['crypt']['method']){
				if(empty($propertyModel['crypt']['mode'])){
					$propertyModel['crypt']['mode'] = self::$methods[$propertyModel['crypt']['method']][0];
				}else{
					$propertyModel['crypt']['mode'] = strtoupper($propertyModel['crypt']['mode']);
				}
				if(empty($propertyModel['crypt']['key'])){
					throw new PorteException('No available encryption key in "'.$type.'.'.$property.'"');
				}
			}
			$propertyModel['type'] = 'string';
			$propertyModel['class'] = 'PortePlugins_CryptType';
			$models->{$type}['properties'][$property] = $propertyModel;
		}
	}
	
	/**
	 * Encryp the value with the AES 128 algorythm and convert it 
	 * into an hexadecimal representation.
	 * 
	 * The result is Mysql compatible with the following statement:
	 * 
	 *     HEX(AES_ENCRYPT($value))
	 * 
	 * Convert into an hexadecimal representation and crypt 
	 * AES 128 compatible mysql HEX(AES_ENCRYPT()) of a srting value
	 * 
	 * @return string The string in hexadecimal
	 * @param string $value The string to crypt 
	 * @param string $key The key for crypt
	 */
	public static function encrypt($value, array $options) {
		if(empty($value)){
			return null;
		}
		if(!empty($options['method'])){
			switch($options['method']){
				case 'AES':
					if(empty($options['key'])){
						throw new InvalidArgumentException('No decrypt key provided');
					}
					$mode = constant('MCRYPT_MODE_'.$options['mode']);
					$value = mcrypt_encrypt(
						MCRYPT_RIJNDAEL_128, 
						$options['key'], 
						str_pad(
							$value, 
							(16*(floor(strlen($value) / 16)+1)), 
							chr(16-(strlen($value) % 16))), 
						$mode, 
						mcrypt_create_iv( 
							mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, $mode), 
							MCRYPT_DEV_URANDOM));
					break;
				default:
					throw new PorteException('Unsupported encryption method: "'.$options['method'].'"');
			}
			
		}
		if(!empty($options['hex'])){
			$value = bin2hex($value);
		}
			
		return $value;
	}
	
	/**
	 * Decrypt an AES 128 encoding value 
	 * stored as an hexadecimal representation into a string.
	 * 
	 * @return string The converted string
	 * @param string $hexValue The string to crypt 
	 * @param string $key The key for crypt
	 */
	public static function decrypt($value, array $options) {
		if(empty($value)){
			return null;
		}
		if(!empty($options['hex'])){
			$value = pack('H*', $value);
		}
		if(!empty($options['method'])){
			switch($options['method']){
				case 'AES':
					$mode = constant('MCRYPT_MODE_'.$options['mode']);
					if(empty($options['key'])){
						throw new InvalidArgumentException('No decrypt key provided');
					}
					$mode = constant('MCRYPT_MODE_'.$options['mode']);
			        $value = mcrypt_decrypt(
			        	MCRYPT_RIJNDAEL_128,
			        	$options['key'],
			        	$value,
			        	$mode,
			        	mcrypt_create_iv(
			        		mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, $mode),
			        		MCRYPT_DEV_URANDOM ) );
			        $value = rtrim(
			        	$value,
			        	((ord(substr($value, strlen($value)-1, 1 )) >= 0 && ord(substr($value, strlen($value)-1, 1 ) ) <= 16 ) ? chr(ord(substr($value, strlen($value)-1, 1 ))): null) );
					break;
				default:
					throw new PorteException('Unsupported encryption method: "'.$options['method'].'"');
			}
			
		}
		return $value;
	}
	
}