CSMA/CA网络协议的无线区块链安全性研究

传统区块链的设计主要面向稳定且传输速率较高的有线通信环境，现有绝大部分的区块链研究都认为通信信道是完美的。随着无线接入网架构的不断演进，以数据验证为基础的区块链势必要考虑无线通信技术的影响。以基于CSMA/CA网络协议的无线局域网为例，节点在无线区块链中广播交易必须遵循MAC规则来竞争无线信道。尤为注意的是，无线信道的频谱资源是极为有限的，那么无线通信协议对交易验证过程的影响会非常显著，同时它也可能成为区块链安全性的瓶颈。该文着力于研究MAC机制中广泛使用的CSMA/CA网络协议对双花攻击进程的影响，利用马尔可夫模型和微积分理论，求解出双花攻击成功的概率。实验结果表明，CSMA/CA网络协议在一定程度上抑制了攻击者的算力，从而降低双花攻击成功的概率，间接地保障了无线区块链的安全。

Security analysis of CSMA/CA in wireless blockchain network

The communication channel of the original blockchain has been considered perfect since it is primarily designed in stable wired communication environment with high transmission rate. However, as the wireless access network architecture evolves continuously, the data verification based blockchain has to consider the impact of wireless communication technology. Taking CSMA/CA based wireless area network as a typical example, any node in wireless blockchain may have to compete for wireless channel to broadcast transactions following MAC mechanism. In particular, due to the scarcity of spectrum resource, the communication transmission delay on the transaction confirmation process may be significant and pose a bottleneck on the blockchain system security. Moreover, this paper focuses on the impact of CSMA/Ca network protocol widely used in MAC mechanism on the process of double flower attack, and uses Markov model and calculus theory to solve the success probability of double flower attack. In the end, simulation results show that CSMA/Ca network protocol inhibits the computing power of attackers to a certain extent, reduces the success probability of double flower attack, and indirectly ensures the security of wireless blockchain.