Distributed Denial Of Service Attack And Prevention Base On Hyperledger

With the success of Bitcoin,Ethereum and other cryptocurrencies,as its underlying blockchain technology has aroused the attention of all sectors of society and has attracted more and more people into it.Different from the traditional centralized information system,it has decentralized,de-trusted,distributed management,collective maintenance,trusted database and other characteristics.It is a set of cryptography,distributed consensus and point-to-point network transmission combination.The goal of this new technology architecture is to provide a lowlevel platform that can safely perform state transitions if all participants do not have a trust basis.Blockchain is divided into three types: public chain,private chain,and consortium chain.The public chain is represented by projects such as Bitcoin and Ethereum,they face to global users and maintain the network through economic reward mechanisms.Private and consortium chain is represented by the Hyperledger project,which is only open to authorized users.It is generally used within or between organizations and has high requirements for consensus algorithms.Due to the characteristics of blockchain technology,it has revolutionized people's perception of trust mechanisms and has also raised the people's attention of blockchain security.At present,there are more and more researches on blockchain security mechanisms.For example,denial of service attacks against blockchain networks,privacy leakage of blockchain network users,etc.,however,most of these studies are based on the common chain.In the private and consortium chain,without the restricting of “transaction fee”,there is no mechanisms to limit the malicious behavior from internal members.In this case,Members can perform denial of service attacks on critical nodes in the network with little cost,thereby,prolonging the response time of normal transactions and even destroying the entire system.Therefore,the robustness of private or consortium chain networks and their resistance to denial of service attacks ability has an important relationshipBased on the Hyperledger project,this paper studies the denial of service attack against the consortium chain platform and analyzes the denial of service attack threat the consortium chain platform facing from the network security level.This paper introduces the proof of work gateway to prevent the attack,and the purpose of proof of work is to limit the transaction sending rate of client,and the gateway is essentially a server responsible for forwarding the client's transaction information,which passes the client's transaction to the block chain network when it validates the client's work.Finally,the experiment show that the gateway can not only effectively control the transaction speed of the client,but also has little impact on the overall performance of the system.