区块链网络安全保障: 攻击与防御

While the security of blockchain has been the central concern of both academia and industry since the very start, new se-curity threats continue to emerge, which poses great risks to the blockchain ecosystem. A systematic study was conducted on the most state-of-the-art research on potential security issues of blockchain. Specifically, a taxonomy was developed by considering the blockchain framework as a four-layer system, and the analysis on the most recent attacks against security loopholes in each layer was provided. Countermeasures that can strengthen the blockchain were also discussed by highlighting their fundamental ideas and comparing different solutions. Finally, the forefront of research and potential di-rections of blockchain security were put forward to encourage further studies on the security of blockchain.