Research On Key Management And Its Application In Fog System

In recent years,the continuous development of fog computing has brought a lot of convenience into our life.Different from traditional cloud computing,which first collects data to the cloud,carries out analysis and calculation based on the efficient Cloud Computing Center,and then returns the calculation result to the user,fog computing can directly analyze and calculate the data from the Internet of things(IOT)devices at the fog node,so as to reduce the bandwidth,computing and storage overhead and improve the quality of user experience.In a general fog computing system,multiple fog devices often need to form a group to carry out cooperative computing to complete large-scale computing tasks.There are many security and privacy issues in the process of group establishment and task allocation.The existing solution is using group key management scheme,so that the fog devices in the group can negotiate the session key,then communicate with others in a secure channel.However,the existing key management schemes still have some problems.Firstly,the dynamicity of the group is a big problem.A malicious node which joins a fog group multiple times within a short time will affect the overall efficiency of the group.Secondly,some key management schemes rely on a centralized trusted computing center,which would lead to the single point of failure.Further,the intermediate parameters generated in the negotiation process are irrecoverable,that is,any network problem may lead to the failure of negotiation.Lastly,in the process of the negotiation,the privacy of fog devices may be leaked.On the other hand,the fog device should get the corresponding reward after completing the computing task,which requires a mechanism that can ensure the fairness exchange between two parties or even multiple parties in the fog system to ensure the rights and interests of the transaction participants.This paper improves the existing key management scheme,and further designs a fairness exchange scheme for the fog system,so as to effectively solve the above problems.The main contribution of this paper includes the following aspects:1.Firstly,the original key management scheme is improved and extended,and the blockchian based key management scheme of fog system is proposed,the main contributions including:· On the basis of the existing scheme,the blockchain technology is introduced to weaken the dependence on the trusted third party and solve the problem that the intermediate parameters may be lost in the process of key agreement.· The existing scheme is redesigned based on asymmetric group,which improves the efficiency and reliability of key agreement.· A Threshold Anonymous Announcement scheme is used to design the group access mechanism,which solves the group dynamic problem and enables the fog device to join/leave the group efficiently and safely?· Based on the existing Proof-of-Work mechanism,a new Designated Prover Proof of Work mechanism is proposed to realize the reliable evaluation of the computing power of fog device?· Furthermore,we also carry out a security prove on the proposed scheme and analyze the feasibility of the scheme through experiments?2.Then,based on the proposed key management scheme,the fog system is further optimized.Focusing on the privacy and fairness exchange in the fog system,a blockchain based fairness exchange scheme in fog computing is proposed,the main contributions including:· Design a privacy preserving mechanism based on the Stealth Address and Coinshuffle to protect the privacy of the participants of the transactions?· Based on the existing two-party fairness exchange mechanism,a new multiparty fairness exchange mechanism is proposed to protect the rights and interests of all parties in a multi-party transaction?· Carrying out a safety analysis on the proposed scheme and prove the feasibility of the scheme through experiments?...