A Protecting Mechanism Against Double Spending Attack in Blockchain Systems

In this research we focus on how to prevent Double Spending Attack (also called 51 % hash rate attack), a particular security issue related to blockchain technology in the current cryptocurrency world. We describe the main idea of our proposed Block Access Restriction (BAR) mechanism, which controls the actual block requests and detects malicious behaviors while transactions have been recorded into a specific block, to protect general miner's privileges and provide fairness in the blockchain network environment. We propose an effective way to prevent this to happen (with detailed steps), discuss how to deploy BAR switch into blockchain networks and how the BAR switch can prevent DSA while the hacker bypasses it. We also present general idea of implementing BAR switch, and point out the importance of dealing with security threat at post-quantum computing era.