As the demand for intelligent services in the Internet of Things continues to increase, the amount of intelligent sensing information is also increasing, and the security of these information has gradually attracted attention. Owing to the openness and the dynamics of intelligent sensor devices, there are a lot of security issues which needed to be resolved for the corresponding intelligent sensing information. In order to protect the transmission security of intelligent sensing information, this paper proposes a security transmission and early warning mechanism for intelligent sensing information in the Internet of Things. In the security transmission and early waring mechanism, we first propose an encryption/decryption algorithm for intelligent sensing information. Then, we build a security transmission algorithm. On that basis, we propose an early warning algorithm of intelligent sensing information. At the end of this paper, we analyze the security of this mechanism and the results of the experiment in order to illustrate its effectiveness. The results show that our proposed security transmission and early warning mechanism are very effective in the Internet of Things.

As the threats to the Internet of Things (IoT) continue to increase, access control is widely used in various IoT information systems. However, due to the shortcomings of IoT devices such as low computing power, it is impossible to use high-performance methods to control user access. Although the emergence of the blockchain provides another way of thinking for access control, the implementation based on the blockchain requires the device to complete the proof of work (PoW) and requires the device to have high computing power. At the same time, most access control schemes existing today are intended for users to use alone, which cannot be applied to the field of multi-user coordinated access. Therefore, this paper proposes a multi-user collaborative access control scheme based on a new hash chain, which uses the identity information of multiple users as the seed value to construct the hash chain, and uses the hash chain as the PoW of the blockchain. An efficiency analysis showed that this method requires only a small amount of hash value calculation and can be applied to IoT systems with low computing power. The security analysis shows that the scheme can resist a variety of attack methods and has high security.

With the advancement of smart devices, the operation and communication of smart grids have become increasingly efficient. Many smart devices such as smart meters, smart transformers, and smart grid controllers are already widely used in smart grids. Thus, a series of complex architectures and a series of communication modes have been formed. However, these smart devices will be exposed to various cyber attacks such as distributed denial of service (DDoS) attack and replay attack. This is because they are open and dynamic. Therefore, there are serious security problems in the complex architectures and the communication modes. In this paper, we propose a multi-domain authentication mechanism based on blockchain cooperation to maintain the security of smart devices. In this mechanism, we propose a series of methods and algorithms, which include initialization method based on blockchain cooperative authentication, dynamic change method of intelligent devices and information, cross-domain authentication algorithm, and cross-domain key cooperative algorithm. To demonstrate the security and effectiveness of our proposed mechanism, we analysed its security and conducted a series of simulation experiments. The analysis and simulation experiments show that our proposed approach is secure and effective.