User-Based CPU Verification Scheme for Public Cloud Computing

In this paper, a user-based CPU verification scheme is proposed for cloud cheating detection. In this scheme, a predefined computational task is constructed for the cloud to execute in our cheating detection process. Then we compare the difference of the actual execution time (recorded by the user) and the theoretical execution time, as to determine whether the cloud is cheating or not. A time-lock puzzle is introduced to construct the predefined computational task, so that the predefined computational task is guaranteed to be executed by the cloud. Our cheating detection process has a higher probability of detecting cloud cheating if using a larger predefined computational task, which in turn costs more time. Further analysis shows that, if the total detection time is limited, it is better to detect cloud cheating using small-scale and short-length cheating detecting processes multiple times, as opposed to large-scale and long-length processes a few times. Finally, the feasibility and validity of the proposed scheme is shown in the evaluations.