Abstract
Office is an open environment where the employees are able to access the PCs in it. However, other people may access the PCs even when they are not the members of the office; if no one is conscious of them. Due to such problem, owner set password as the secure policy to protect their PC. But individuals tend to use weak password since it is easy for them to remember it; we think it is not secure. In this thesis, we observe that employees have behavior of walking the familiar path to their office. Base on the observation, we proposed SOP-KPP system, which leverage knowledge of pedestrian paths as the access control policy. In SOP-KPP, we deployed amount of gateways and could use them to depict the pedestrian paths. Individuals must pass the gateways and aggregate their digital signatures through the path to their office with mobile devices. Till individuals reach the PC, they would send aggregated signatures to PC to access it. If signatures are aggregated in right sequential order, PC would unlock itself. Besides we use short-range wireless link to bond mobile devices to PC for detecting the presence of user. If user left the PC, it will lock the screen to protect itself. Furthermore, we made a serial of experiments to evaluate the performance and the result showed that time spent at each gateway is less than 10 seconds and power consumption is 10 percents of the total power capacity per 8 hours for pulling protocol.