/*
     * 生成RSA私鑰和公鑰
     * @success array privKey,pubKey
     * */
    public function pkey_new(){
        $config = array(
            "private_key_bits" => 1024,//位數
            "private_key_type" => OPENSSL_KEYTYPE_RSA,
        );
        $res = openssl_pkey_new($config);
        openssl_pkey_export($res, $privKey);//私鑰
        $pubKey = openssl_pkey_get_details($res);
        $pubKey = $pubKey["key"];//公鑰
        return array('privKey'=>$privKey,'pubKey'=>$pubKey);
    }