Security for wireless sensor networks

Wireless sensor networks are becoming more and more popular; however, with the advent of smart dust the security for wireless sensor networks is still a trouble. Resolving security for wireless sensor networks, an important problem is key distribution. In this paper, we show how the key distribution problem can be dealt with in environment and we make full use of asymmetric cryptographic technique to devices with capable processors, then the security has greatly improved. At the beginning, we hoped once a node can communicate securely and simply with other nodes to generate a symmetric key, and sent it in the clear to its neighbors; however, we found this primitive mechanism was an apparent insecurity way. Then we have improved this method, updated key and used multi path secrecy amplification and multi hop key propagation; now, we can build up extremely resilient security networks in the place where at most communication can be subverted easily. In this process, we have built a secure system and it works well. We believe security systems can become an integral part of practical sensor networks.