/**
 * This class extends the basic functionality of Yii's CSecurityManager with
 * methods to implement asymmetric encryption in small applications. To use this
 * component you need the OpenSSL PHP extension.
 * 
 * @author  i.amniels.com
 * @version 0.1
 * 
 * @license Everyone is permitted to copy and distribute verbatim or modified
 * copies of this document as long as there is a hyperlink to
 * http://i.amniels.com/mysql-database-encryption-using-public-private-keys
 * without the nofollow attribute published with the copy. This document comes
 * without warranty.
 *
 * How to use this component:
 * 1. Copy this file to the components directory. Enable it in the application
 *    configuration file under components:
 * <code>
 *  'securityManager'=>array(
 *           'class'=>'SecurityManager',
 *           'asymPublicKeyFile'=>'application.data.publickey',
 *  ),
 * </code>
 * 2. Generate a key pair using generateAsymNewKeyPair() once (!!).
 * 3. Encrypt some data with the public key using asymEncrypt($data).
 * 4. Store a private key in the user's session using storeAsymPrivateKey($key).
 * 5. Decrypt the encrypted data using asymDecrypt($data).
 */