Review of trusted cloud computing based on proof-based verifiable computation

To a very great extent, trustworthiness is a critical factor for the large-scale popularity of cloud computing. To instill greater confidence in computations and data outsourced to the cloud service providers, the client should verify the correctness of computation results returned by cloud service providers. Verifiable Computation is the very solution that can let the client check the correctness of a remotely executed computation by inspecting a proof by the remote cloud service providers, without reexecuting the computation. Recent works in verifiable computation have received broad attention in both the academic and industrial research, and the pace of progress in verifiable computation has been rapid. A number of projects have reduced the verifiable computation theory to near-practice in the context of implemented system and have mode it become a constructive approach to trusted cloud computing. The goal of this paper is to survey this blossoming area of research, especially in the cloud computation area. This paper first presents the problem that proof-based verifiable computation is solving in a unified framework, together with some of key theory that has developed to solve it, and then describes design principle and basis theory of verifiable computation protocol. Based on systematic analysis and summary of the related works on verifiable computation, this paper presents a category of verifiable computation protocols according to the two dimensions which are main processes including compile processing and proof system. The verifiable computation protocols in this paper use compiler based on Fairplay and Benjamin compiler to compile the protocol, and generate model of computation for proof system. It can be divided into two approaches according to main process of compiling, as: verifiable computation protocol based on simple compiler and verifiable computation protocol based on complex compiler. It can be divided into two approaches according to proof system, as: verifiable computation protocol based on interactive proof system and verifiable computation protocol with preprocessing based on argument system. We do not discuss verifiable computation without preprocessing based on argument system, and the choice of scope is to make this paper manageable because such protocols are based on short PCPs and still impractical. This paper also covers basic definition, principle and process of typical protocols, application scenarios, performance analysis in each of our classification. At the end of this paper, we summarise some of open questions in this area. The biggest issue in this research area is performance. Also the computational model and underlying theory are a critical area of focus. And other research directions involve changing the model and goal of verifiable computation protocol, and privacy requirements of procotol in the context of cloud computing. All our works will play a role in promoting the further research of cloud computing security based on verifiable computation. And we believe that the real application of these techniques to cloud computing will appear in the next few years with the rapid progress in verifiable computation.