Research On Mechanisms Of Data Forwarding And Security In AMI

Advanced Metering Infrastructure(AMI) is a very important part of smart grid and a research focus which gets more and more study and application. By AMI, utility not only can collect, store, analyze and provide metering data from some devices such as smart meters, but also carry control messages and upgradeable firmwares to the smart meters, realizing bidirectional communication between utility and end users. This thesis focuses on the data forwarding mechanisms and application layer security mechanisms of AMI.In the aspect of data forwarding mechanisms, this thesis presents a data forwarding mechanism, the core of which is the use of IPv6 and design of an enhanced coordinator. With the consideration of saving battery energy, this thesis presents an improved routing algorithm i AODV for designed data forwarding mechanism on the base of AODV routing algorithm. For the improved algorithm, this thesis presents a role based differentiated HELLO message time interval set idea and a routing item statistics based HELLO message time interval set algorithm. With OPNET simulator, this thesis tests performances of i AODV and two kinds of topologies which are based mesh network and tree network respectively. Simulation results show that the improved routing algorithm decreases network delay at the same time of saving energy, and mesh network topology has better performance comparing to tree network topology.In the aspect of application layer security mechanisms, this thesis studys three security mechanisms, including identity authentication, secure transmission and key management. In the mechanism of identity authentication, this thesis presents a double keys hash chain based double factors identity authentication approach. Security analysis shows that this approach is very secure. In the mechanism of secure transmission, this thesis comprehensively uses a light-weight symmetric cryptography algorithm, a hash algorithm and a lossless data compression algorithm, providing three services containing data confidentiality, data integrity verification and data compression. On the base of designed transmission module, this thesis redefines the application protocol data unit format. In the mechanism of key management, this thesis presents an Elliptic Curve Cryptography based key management solution which introduces generating methods of point-to-point sharing key, group sharing key and global sharing key in the modes of unicast, multicast and broadcast respectively. Theoretical analysis shows that this solution is very secure, reliable and flexible. This thesis implements designed security mechanisms on the base of Open SSL that is a famous open source cryptographic library, then tests performances of these security mechanisms with five test items, including connectivity, symmetric ciphering speed, key exchange speed, digital signature speed and hash chaining speed. Experimental results show that the designed security mechanisms are very efficient and can satisfy high demand of real-time performance in AMI very well.