Research Of Key Distribution Strategy For Industrial Wireless Network

With the rapid development and the increasingly maturation of wireless sensor networks, the wireless networking technology has been gradually used into the industrial automation areas since 90's of 20th century. Because of its low-cost, low-power, high degree of flexibility, scalability and other properties, wireless networking technology has become one of the major development directions in the field of automatic control network. In 2002, the concept of industrial wireless network was officially proposed, which made it another research focus followed the field bus technology. WIA-PA(Wireless Networks for Industrial Automation-Process Automation) is a technical specification of industrial wireless network with independent intellectual property right, which was researched and developed by the Chinese Academy of Sciences, Southwest University, Chongqing University of Posts and Telecommunications, and more than 10 units under the support of National High Technology Research and Development Program of China(863 Program). This technical specification was adopted by IEC in 2008 and included in the international standard-setting plan. As WIA-PA was used to industrial real-time monitoring, and the openness of wireless networks, security is particularly important. So how to improve the security of WIA-PA is an important issue.Based on the characteristics of limited resources of WIA-PA, it needs to cut down the cost in communication and computation of the security scheme while ensuring the security in communication as far as possible. As the wired network of non-symmetric key management techniques are not suitable for resource-limited wireless WIA-PA, using symmetric keys is the only choice to achieve the security of communication. Therefore, the issue of key management should be solved firstly among all the issues in security.The author of this paper, under the participating in the research and development work of WIA-PA and the analyzing of the current key management protocol of distributed and cluster-type wireless sensor networks, contrary to the deficiency of LEAP in high consumption for setting up Pair-wise key, disable for identifying equipment and imperfect for key updating and node adding; combined with the characteristics and security needs and risks of WIA-PA, based on the LEAP protocol, propose a centralized and classified key management scheme TCC for WIA-PA based on key management tree. This scheme using different types of key encrypts different types of communication, and constructs a key management tree to realize device identification, key distribution and updating. And the tree is used as the carrier of centralized management.This paper firstly analyses the current, most widely studied scheme of the key management protocol of distributed and cluster-type wireless sensor networks, and points out the deficiency in security and energy consumption that used in WIA-PA. And then, by analyzing the existed key management protocol, it is found that only LEAP protocol key management solution is closest to the WIA-PA network application. Therefore, On the basis of the LEAP protocol, based on the ideas of different types of communication requires different communication key, a variety of key management strategy TCC is proposed. Contrary to the deficiency of LEAP in key updating, withdrawing, node deleting, and new node adding, combined with the network security architecture of WIA-PA, TCC manages the whole network key by constructing a key management tree and uses the gateway to control the pair-wise key distribution. It enhanced the centralized control of the network by gateway and improved the mechanism of key update and node addition, deletion. In order to ensure safe and reliable broadcast, one-way key chains for broadcast authentication and the key-chain tail for communication key updating are used. At the same time, for the sake of ensuring strong freshness message, the Nonce authentication mechanism is also used. Finally, under the configuration of the network in this paper, the simulation results show that, the energy consumption of pair-wise key establishment of TCC is decreased by 14.2% compare with LEAP and storage space requirement of TCC is decreased by 6.82%. Theoretical analysis and experimental results show that, TCC is more energy-efficient, securer and more scalable than LEAP, which proves that TCC is effective to apply to WIA-PA.