Zend_Crypt_Rsa implant

Rsa.php

<?php
/**
 * CORE
 * Custom extended library for Zend Framework 1.10.x
 * 
 * Copyright (c) 2011, Sarjono Mukti Aji <http://simukti.net/>
 * All rights reserved.
 * 
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this libraries source code.
 */

/**
 * Rsa encryption wrapper with openssl private key
 *
 * @category Core
 * @package Utiliyy
 * @subpackage Rsa
 * @author Sarjono Mukti Aji <http://simukti.net/>
 * @copyright (c) 2011 - Sarjono Mukti Aji <http://simukti.net/>
 */
class Core_Utility_Rsa
{
    /**
     * SSL private key
     * @var string
     */
    protected static $_privatekey;
    
    /**
     * Set ssl key path. I set it from application bootstrap.
     * 
     * @param string $privatekey private key path
     * @throws Core_Exception_InvalidArgumentException when private key was not set yet or file does not exists
     */
    public static function setPrivateKey($privatekey)
    {
        if (null === $privatekey) {
            throw new Core_Exception_UnexpectedValueException('Your private key was not set yet.');
        }
        
        if (! file_exists($privatekey)) {
            throw new Core_Exception_InvalidArgumentException(sprintf('Private key %s is not found.', $privatekey));
        }
        
        self::$_privatekey = $privatekey;
    }
    
    /**
     * Get ssl private key path
     * 
     * @return string private key path.
     */
    public static function getPrivateKey()
    {
        return self::$_privatekey;
    }
    
    /**
     * Encrypt string
     * 
     * @param string $string String to encrypt
     * @return string Encrypted string 
     */
    public static function encrypt($string)
    {
        if (! is_string($string)) {
            throw new Core_Exception_InvalidArgumentException('Param to encrypt is not a string.');
        }
        
        $rsa = new Zend_Crypt_Rsa(array(
                   'pemPath' => self::getPrivateKey()
               ));
        
        $encrypted = $rsa->encrypt($string, $rsa->getPrivateKey(), Zend_Crypt_Rsa::BASE64);
        return $encrypted;
    }
    
    /**
     * Decrypt string
     * 
     * @param string $string String to decrypt
     * @return string Decrypted string
     */
    public static function decrypt($string)
    {
        if (! is_string($string)) {
            throw new Core_Exception_InvalidArgumentException('Param to decrypt is not a string.');
        }
        
        $rsa = new Zend_Crypt_Rsa(array(
                    'pemPath' => self::getPrivateKey()
               ));

        $decrypted = $rsa->decrypt($string, $rsa->getPublicKey(), Zend_Crypt_Rsa::BASE64);
        return $decrypted;
    }
}