private $privateKey = 'MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAL3E/1HucWr/LDhBGx57GhpF74oO0EaQdoNBYlGY5ce/pnxZxwCt/IeTo715wOaVP85FPn1HexLYfgQmminqXKvLwnW4ZLOMttihWH13THIQJAR+8jR1t9NZWQaxIrogw/sNgNQQgXlEHOCdmYU/bwZ1kOTMmeuDbebB4NH+WtFyCEfaW6z12SL2YQXoUL5s2K6QJBAJfGIBuPh52uKZAPaBOk/l010/uPEugWXoMRmLMkyzyu+0GwY3aPK1dgtsIoyKMbys6USPw7CkYL9YRWBWaZGrE=';
   
//params指的是请求的数组（不含SIGN）
 protected function ras_sign($params)
    {
        if(!empty($params)){
            $p =  ksort($params);
            if($p){
                $str = '';
                foreach ($params as $k=>$val){
                    if($val){
                        $str .= $k .'=' . $val . '&';
                    }
                }
                $strs = rtrim($str, '&');
                $privateKeyPem = "-----BEGIN PRIVATE KEY-----\n"
                    . chunk_split($this->privateKey, 64, "\n")
                    . "-----END PRIVATE KEY-----";
                // 2) 载入私钥
                $privateKey = openssl_pkey_get_private($privateKeyPem);
                if (!$privateKey) {
                    die("私钥不合法");
                }
                // 3) 分段加密（1024bit RSA: 每段最大 117 字节）
                $maxBlockSize = 117;
                $encrypted = '';
                $dataLen = strlen($strs);
                for ($i = 0; $i < $dataLen; $i += $maxBlockSize) {
                    $block = substr($strs, $i, $maxBlockSize);
                    openssl_private_encrypt($block, $encBlock, $privateKey, OPENSSL_PKCS1_PADDING);
                    $encrypted .= $encBlock;
                }
// 4) 和 Java 一样，使用 Base64 URL Safe 编码
                $encryptedBase64 = rtrim(strtr(base64_encode($encrypted), '+/', '-_'), '=');
                return $encryptedBase64;
            }
        }
        return '参数错误';
    }