ERCA: efficient and robust cipher algorithm for LTE data confidentiality

Abstract

In this paper, a new ciphering algorithm is proposed for Long Term Evolution (LTE) data confidentiality. The proposed cipher scheme is based on a novel stream cipher framework which uses Substitution-Diffusion (SD) structure to provide key-streams that possess acceptable cryptographic performance (avalanche effect and key sensibility). Standards have been already adopted by 3GPP for LTE data confidentiality; EEA1, EEA2, and EEA3 which are based on Snow 3G, Advanced Encryption Standard (AES), and ZUC, respectively. Although the above mentioned algorithms have sufficient security strength against attacks, our solution is constructed to ensure less complexity with similar security strength. The proposed algorithm consists of an addition layer and a modified RC6 substitution layer which could require no memory and has stronger cryptographic properties compared to RC6. Furthermore, a new dynamic non-invertible diffusion layer technique is introduced, which is constructed from the output of the substitution layer. Theoretical and simulation results show that our algorithm is immune against liner, differential, chosen/known-plain-text, brute force and statistical attacks. Equally important to note, our proposed cipher algorithm has a lower computational time compared to AES, and could be adapted for other kinds of wireless networks.