1 Introduction
With the advent of the age of cloud computing and mobile computing, computation outsourcing is becoming a popular computing paradigm. Clients with low computation power or resources can off-load their computation tasks to clouds, which are equipped with more computing resources. The clients could be mobile phones, companies, and senor nodes in a wireless sensor network, etc. Since there are a lot of such applications, this paper investigates the computation outsourcing problem with a case study of the linear regression (LR) task.