Blockchain Security Technology Based on the Asynchronous Transmission Mode of IoT Technology in Smart Cities

With the rapid development of information technology, issues such as network security and privacy protection have attracted more and more attention. The traditional way to solve these problems is to design complex cryptographic protocols to strengthen security, but the traditional solutions are based on centralized systems. The stronger the control of the central organization of the system, the more vulnerable it is to attackers. However, the blockchain technology that has emerged in recent years has revolutionized the use of decentralized solutions. The privacy and security issues of smart cities have become particularly important. Safety technology research in cities has also become very important. In order to better study the security technology in smart cities, this paper uses asynchronous transmission mode to study the blockchain security technology in smart cities on the premise of the Internet of Things technology. This paper compares and analyzes the data collection, sorting and calculation of the cryptographic elliptic curve algorithm before and after the improvement in the blockchain technology, the throughput and delay of different consensus algorithms, and the percentage of the computing power of the consensus algorithm. Transaction security. The final result shows that, the improved elliptic curve algorithm has more obvious advantages than the previous elliptic curve when the value of k is larger, and the higher the value of k, the faster its single scalar multiplication speed; The improved elliptic curve algorithm has more obvious advantages than the previous elliptic curve when the value of k is larger, and the higher the value of k, the faster its single scalar multiplication speed; The consensus algorithm has the largest percentage of computing power, BTC.com, accounting for 20.4%, and the smallest percentage of BWPool's computing power is only 1%. Therefore, it can be concluded that the decentralization and consensus mechanism of blockchain security technology can well guarantee the communication security of the Internet of Things.