During pandemic situations, remote work security and reliability become more important for sustainability. The main problem in remote working is providing a reliable internet connection between remote working employees and remote systems. Lack of internet connection issues cause remote working problems, and some companies allow employees to work on untrusted personal computers, which causes untrusted and unmanageable IT systems. According to these problems, this study proposed a lightweight, offline authentication scheme for the secure remote work environment. The proposed model is designed for LPS (Lightweight Portable Security) devices, and these LPS devices provide portable USB bootable images with a secure environment for this connection and trust problems. LPS devices are single USB dongles to make users more dependent on these LPS devices. This design provides mobile application-dependent authentication to provide strong user authentication with 2FA (2 Factor Authentication), which is something you have (mobile phone and USB dongle) and something you know (mobile PIN). Also, the proposed model provides geofencing between USB dongles and Mobile phones to offer robust security.