In this paper, a new transposition cryptosystem scheme is proposed, in which a rotation session key is designed for a mobile user to secure access the multiple sessions of mobile text chatting (MTC). This is a block cipher adopts a classical substitution combined a text-matrix rotation operation in order to enhance the protection MTC over Internet. The scheme is entirely dependent on the only secret key. The session key is designed by a pseudo random function which the input is length of secret key. Due to the characteristics of easy and fast computation, it will be a low cost to achieve the useful cryptosystem. Finally, its security strength is strong compared to other approaches under the frequency analysis.
The 28th IEEE International Conference on Advanced Information Networking and Applications