视频号的消息推送解密是纯密文模式，这个该怎么操作？密钥是视频号小店自研里设置的的密钥？

{"ToUserName":"gh_*","Encrypt":"yR1HA0sogxrNsKV5P+ccnXa+7SMWkxcbYKbDIUhKPpLoYVreMcgar8h108f7Irp1aVmI1sTLfKN6gf8nvfINCRtH8iJBGBVm\/BubJLL\/tUKDO6aYsszDkOw1AguMSYm55suk\/Wna7nCV25oOT9EC6NCfUkXML\/0KZXuu1RH6lrtoYHdWZUer2SY9oArRk36JScUbqBbIJ6\/cqXvecbnXbxXzvw4Nc3G85dFl4404EZqyQmug4cs+vtna\/TyzVsmSJ6FFF41RhVux0HzZjwqaVEelpFkNiPuTLWTfB+uNKbeqcCNxFMPZMn0efzqYAdzYFlKfzbx7hA=="}