基于区块链的密钥更新和可信定位系统

With the development Internet of Things (IoT), the number of intelligent devices is increasing rapidly. The ad hoc network mode of wireless intelligent devices has dynamic topology and decentralized distribution and does not have a fixed infrastructure. However, these features bring many problems to the security of communication and positioning. Firstly, the combination of symmetric and asymmetric encryption schemes is applied to achieve secure communications between IoT devices, while once a private key is lost or leaked, it is hard to synchronize the latest keys in the whole ad hoc network. Secondly, complicated interaction and computation are usually needed for key agreement among devices in ad hoc networks. Thirdly, under some circumstances, it can be a great challenge for ad hoc intelligent devices to receive signal from the trusted third party which is also required to be always online, but the existing ad hoc positioning system cannot remain secure when lacking of trusted third party like base station. Finally, the existing positioning algorithm cannot protect positioning signal untampered, and it is difficult to ensure the accuracy of the positioning displayed by each mobile device in the ad hoc network. In view of the above problems, we propose this system by using blockchains established between wireless IoT devices as the trusted infrastructure to record the key update chain corresponding to the user identity and facilitate the session key agreement among multiple users. Based on the consensus mechanism, the system enables trusted mutual positioning among IoT devices when there is no or weak positioning signal, and it protects the authenticity of positioning information sent or received by devices. The system can be built by the existing secure cryptographic algorithms, enabling secure and efficient key updates and trusted positioning, and it is adapted for use in actual devices in secure IoT systems.