As we know, compared with the asymmetric encryption methods, the symmetric encryption methods have the advantage that the encryption and decryption are very fast, making them very suitable for transmitting large amounts of secure data. For a long time, its distribution method has been one of the research focuses in secure communication, especially the distribution of symmetric keys. The key is an important part of modern cryptography. Finally, we reason the security of the key distribution protocol with formal analysis tools. Next, we design a key distribution protocol and a key distribution system, which consists of a Management Center, a Packet Forwarding Network, and Users. Then, these sets are processed, respectively, by correcting outlier, normalizing, quantizing, encoding, and reconciling so as to be able to realize key distribution between two sides. By randomly determining the forwarding path of packets, we can get customized transmission delay sets. On the Internet, we have deployed 7 forwarding hosts. Accordingly, we propose a method to customize transmission delays. Based on the experimental observation, we find that the statistical characteristics of their transmission delays are about the same if any two terminals transmit the equal-length packets on the Internet and are different for different transmission paths.
In this paper, a novel key distribution scheme based on transmission delay is proposed. However, the traditional key distribution scheme is high in cost and complicated in calculation, so a lightweight key distribution scheme is urgently needed. With the development of IoT (Internet of Things), the demand for security is increasing day by day.