<?php
/**
 * Zeed Platform Project
 * Based on Zeed Framework & Zend Framework.
 * 
 * BTS - Billing Transaction Service
 * CAS - Central Authentication Service
 * 
 * LICENSE
 * http://www.zeed.com.cn/license/
 * 
 * @category   Zeed
 * @package    Zeed_ChangeMe
 * @subpackage ChangeMe
 * @copyright  Copyright (c) 2010 Zeed Technologies PRC Inc. (http://www.zeed.com.cn)
 * @author     Zeed Team (http://blog.zeed.com.cn)
 * @since      Jul 5, 2010
 * @version    SVN: $Id: Abstract.php 5517 2010-07-05 08:12:54Z woody $
 */

/**
 * A class for implementing a Signature Method
 * See section 9 ("Signing Requests") in the spec
 */
abstract class Zeed_OAuth_Signature_Abstract
{
    /**
     * Needs to return the name of the Signature Method (ie HMAC-SHA1)
     * @return string
     */
    abstract public function getName();
    
    /**
     * Build up the signature
     * NOTE: The output of this function MUST NOT be urlencoded.
     * the encoding is handled in OAuthRequest when the final
     * request is serialized
     * @param OAuthRequest $request
     * @param OAuthConsumer $consumer
     * @param OAuthToken $token
     * @return string
     */
    abstract public function buildSignature($request, $consumer, $token);
    
    /**
     * Verifies that a given signature is correct
     * @param OAuthRequest $request
     * @param OAuthConsumer $consumer
     * @param OAuthToken $token
     * @param string $signature
     * @return bool
     */
    public function checkSignature($request, $consumer, $token, $signature)
    {
        $built = $this->buildSignature($request, $consumer, $token);
        return $built == $signature;
    }
}

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