Design and Implementation of a Secure Peer-to-Peer File Transfer System Based on IP Multicast and Diffie-Hellman Algorithm

In order to perform peer-to-peer file transfer in LAN and ensure data security during the transfer process, nodes are discovered and connected through the node discovery protocol, while key agreement and symmetric encryption algorithms are used to ensure transmission security. On the basis of IP multicast, the protocol stack of node mutual discovery is designed and implemented. When a secure connection is established between nodes, the Diffie-Hellman algorithm is used to negotiate a shared key. Using this shared key, the communication data between the two parties is encrypted by TEA algorithm. Finally, a secure peer-to-peer file transfer system is implemented. Experiments show that: under the condition of LAN, the nodes can be discovered mutually through the node discovery protocol designed in this paper, and the nodes can perform secure file transmission under the protection of key agreement and symmetric encryption algorithm. This secure peer-to-peer file transfer system based on IP multicast and Diffie-Hellman algorithm can effectively realize the secure transfer of peer-to-peer files in LAN, thus solving a class of network security problems.