A Composable Model And Protocol Design For Rationally Delegated Computing

Delegation of computation is a computing method to solve task authorization in cloud computing and big data environment.By introducing the idea of game theory into the traditional delegation of computation,the participants are regarded as self-interested people based on rational thinking,and it is of more practical significance to explore the influence of their preferences and behaviors of the rational participants on the calculation task.As a formal method for analysis and design of security protocols,the universally composable(UC)framework is suitable for the asynchronous and concurrency of protocol execution,and for the complex network environment with multiple users and multiple instances.Therefore,exploring the security of rational delegation of computation in the UC framework is more in line with the practical security requirements.This paper studies composable model and protocol design for rational delegation of computation based on game theory,delegation of computation and universally composable security theory,mainly including composable mechanism for delegation of computation based on rational adversary,fair and rational delegation of computation scheme in the UC framework,and rational delegation of computation scheme based on reputation and contract theory in the UC framework.The details are as follows:1.Aiming at the composable security problem of rational delegation of computation,a composable mechanism for delegation of computation based on rational adversary is designed.Firstly,a rational external adversary is introduced,the interaction mechanism between the delegator,the calculator and the external adversary is described by designing the delegation contract,the corruption contract and the betrayal contract,and then the tripartite game model is established.Secondly,by analyzing the correctness and reliability of the calculation results,the privacy of the data,the rational decision-making of the participants and the adversary model,the ideal functionality for the rational delegation of computation based on the universally composable security theory is constructed.Thirdly,a rational delegation of computation protocol is designed based on fully homomorphic encryption technology,which can securely realize the ideal functionality.Finally,the analysis of the scheme shows that the designed protocol can satisfy correctness and UC security.2.In view of the economic fairness between the delegator and the calculator,a fair and rational delegation of computation scheme in the UC framework is proposed.Firstly,a dynamic two-party game with perfect information is established by analyzing the attack self-interest behaviors between the delegator and the calculator.Secondly,a fair and rational delegation of computation scheme is designed by using the blockchain model of cryptography.In the ideal world,the ideal functionality for fair and rational delegation of computation which satisfies the security requirements is constructed.And in the real world,smart contracts and succinct commit-and-prove are used to design a fair and rational delegation of computation protocol.Finally,the scheme is analyzed and proved.The results show that the protocol can securely realize the ideal functionality,and when both the delegator and the calculator choose the honest behavior,the utility of both parties reaches the maximum,and there is no need to call the third-party contract for arbitration.3.To solve the issue of information asymmetry between the delegator and the calculators,a rational delegation of computation scheme based on reputation and contract theory in the UC framework is presented.Firstly,a global reputation incentive model is proposed by combining direct reputation and indirect reputation,so that the delegator can choose the appropriate calculators according to his own reputation requirements.Secondly,an optimal incentive mechanism satisfying individual rationality and incentive compatibility constraints is designed by using the information screening model and the moral hazard model of hidden actions in contract theory.Thirdly,a security model for rational delegation of computation based on reputation and contract theory is designed by using the universally composable security theory,and a real protocol is presented which can securely realize the ideal functionality.Finally,the protocol analysis shows that the protocol still satisfies the security requirements in the UC framework.