Research On Symmetrical Cipher Algorithm In Security Mechanisms Of Wireless Sensor Network

Wireless sensor network (WSN) is widely applied both in military and civil fields. WSNs pose a number of security challenging problems. For instance, WSN systems have very limited cost and power supply by its nature, which leads to limited ability of computing and communication. One of the most critical WSN issue is security issue, which is becoming the key barrier for practical applications.WSN mostly use symmetrical key technology, but rarely public key technology because of node function limit. IEEE 802.15.4 protocol builds a series of security mechanisms based on AES (Advanced Encryption Standard) algorithms. Based on symmetrical key technology, SPINS (Security Protocols for Sensor Network) put forward useful Sensor Network security scheme in security mechanisms. In this dissertation, the focus is mainly on several problems for symmetrical key cryptography in security mechanisms of wireless sensor network as follows:Firstly, AES(Advanced Encryption Standard) algorithms is analyzed and a low-cost, high-security AES coprocessor for wireless sensor network is Implemented in this dissertation. For the low-cost request for micro-sensor node in wireless sensor network, sbox unit module that consumed most chip area is firstly consided in the design process. Employing reusing and sharing between the encryption and decryption processes for different blocks, a compact encryption and decryption system using only four sharing S-Boxes instead of 20 S-Boxes is obtained. Our design proposes use of composite field data path for the SubBytes and InvSubBytes transformations.Secondly, this dissertation discusses common block ciphers analysis, and focus mainly on. Based on the discussion of AES power analysis theory, a novel power analysis immune scheme is proposed. This method divides the data-path of AES into two parts: inhomogeneous S-Boxes instead of fixed S-Boxes are selected randomly to disturb power and logic delay in the non-linear module; at the same time, the general masking strategy is applied in the linear part.Thirdly, common block ciphers modes of operation are discussed in this dissertation. A fast authentication mode based on chaining & counter (CCTR) is put forward, and its operation, speed are researched in this paper. Focus on AES-CCM-128 modes of operation which IEEE802.15.4 protocol uses, and CCM-AES processor architecture are discussed, includes authentication module, encrypt module and controll module.MDS, SHA and RIPEMD hash function are compared with each other in performance in this dissertation. On account of Algorithms operation speed and security performance, SHA Algorithms is firstly adopted. By folding the data path of SHA-1 algorithm and using CSKA(Carry Skip Adder) to optimize the critical path, the proposal implementation obtains higher performance and lower area cost.Finally, IEEE802.15.4 security mechanisms of wireless sensor network and SPINS (Security Protocols for Sensor Network) are discussed. Aim at the base request of wireless sensor network security, security communication between two node is obtained by putting forward the method that a private key is shared between a node and the base station, and counter mode encrypt method and MAC(message authentication code) are adopted. Then ProPose the Methods that adopt delay propagation key chain to secure the broadcast communication.