OAuthSimple::_generateSignature PHP Method

    private function _generateSignature($parameters = "")
    {
        $secretKey = '';
        if (isset($this->_secrets['shared_secret'])) {
            $secretKey = self::_oauthEscape($this->_secrets['shared_secret']);
        }
        $secretKey .= '&';
        if (isset($this->_secrets['oauth_secret'])) {
            $secretKey .= self::_oauthEscape($this->_secrets['oauth_secret']);
        }
        if (!empty($parameters)) {
            $parameters = urlencode($parameters);
        }
        switch ($this->_parameters['oauth_signature_method']) {
            case 'PLAINTEXT':
                return urlencode($secretKey);
            case 'HMAC-SHA1':
                $this->sbs = self::_oauthEscape($this->_action) . '&' . self::_oauthEscape($this->_path) . '&' . $parameters;
                return base64_encode(hash_hmac('sha1', $this->sbs, $secretKey, TRUE));
            default:
                throw new OAuthSimpleException('Unknown signature method for OAuthSimple');
                break;
        }
    }