Group Key Update Method for Improving RC4 Stream Cipher in Wireless Sensor Networks

To secure the wireless sensor network (WSN) for data transmission, RC4 stream cipher is able to provide the advantages of fast performance and simplicity in resource constrained environment. Since RC4 stream cipher is a symmetry key encryption algorithm, initialization vector (IV) has been normally used to provide variation of encryption from different sensor nodes in the WSN. In this case, the IV length must be long enough to avoid repetition. This paper presents a group key update method that enhance the security of RC4 from cryptanalysis without increasing the length of key and IV. Experiments show that the implementation of this method uses minimal resource from the wireless sensor device. The results verify that the new generated key and the key update time are random, untraceable and unpredictable. When the number of sensor nodes is increased, the key update time is more random.