Research On Scalability Of Blockchain Based On Computing Offloading And Storage Optimization

The high computing and storage resources required by blockchain hinder its development.In particular,it is difficult to realize large-scale application of blockchain in resource-limited environments,including the Internet of Things.Offloading complex blockchain tasks at Io T terminal users to the edge or cloud is an effective solution to relieve the computing pressure on terminal users.Cloud/edges provide paid computing resources to Io T terminal users,such that the terminal users are able to benefit from performing blockchain tasks.Therefore,resource allocation and pricing of computing resources at the cloud/edges have a significant impact on the revenues of cloud/edges services provider and users.Erasure-code technology is an effective measure to reduce the blockchain data storage redundancy.However,the reduction of data storage redundancy will reduce the security of blockchain data and improve the latency of data reading.Therefore,focusing on the above problems,this thesis studies the computing offloading of mobile blockchain based on cloud/edge computing and the storage optimization of blockchain based on erasure-code to improve the scalability of blockchain.The main research contents are as follows.(1)Focusing on the computing offloading problem of mobile blockchain based on cloud/edge computing,an efficient Iterative Greedy-and-Search based resource allocation and pricing algorithm(IGS)was proposed.This thesis builds a computing offloading framework including a cloud,multiple edge servers and multiple Io T terminal users(miners).Cloud/edges service provider(CESP)provides cloud and edge computing resources for Io T terminal users.Io T terminal users offload computing tasks to cloud/edges to perform blockchain services.We formulate a Stackelberg game with CESP as the leader and users as the followers for cloud/edge computing resource management.We prove the existence of Stackelberg equilibrium and analyze the equilibrium.We then model the resource allocation and pricing at the CESP as a mixedinteger programming problem(MIP)with the objective to optimize the CESP's revenue and propose an efficient iterative greedy-and-search based resource allocation and pricing algorithm(IGS).Simulation results show that algorithm IGS can effectively improve the revenue of both the CESP and the Io T terminal users.(2)To solve the storage optimization of blockchain based on erasure-code,a latencyaware Encoded block Allocation algorithm(LEA)was proposed.In the erasure-code based BFT permissioned blockchain,this thesis studies the decision problem of storage quantity and storage location of encoded blocks to obtain good data storage and reading performance under the constraint of data security.Firstly,algorithm LEA solves the relaxation problem of the decision problem and the dual problem of the relaxation problem.Then algorithm LEA determines the storage quantity and storage location of each data block according to the optimal solution of the relaxation problem and its dual problem.Finally,the block storage allocation scheme is adjusted to satisfy the constraints of the decision problem.Theoretical analysis proves that algorithm LEA is an approximation algorithm of ln3+2.The simulation results show that the algorithm LEA can obtain good data storage overhead and data read delay overhead.