Secure Outsourcing of Modular Exponentiation with Single Untrusted Server

Cloud computing allows resource-constrained users to outsource the complex computation tasks to the cloud server. During the process, users should keep their input and output privacy. However, the cloud server may not be honest, it may return an incorrect result for economical factors. So users have to check the correctness of the results they receive from the cloud server. In this paper we propose an outsourcing algorithm of modular exponentiations with single untrusted cloud server. During the outsourcing process, the computation modular exponentiations is hidden to server, and the users can verify the result the server returns with high checkability.