International Association
for Cryptologic Research

The 3GPP Task Force recently supplemented mobile LTE network security with an additional set of confidentiality and integrity algorithms, namely 128-EEA3 and 128-EIA3 built on top of ZUC, a new keystream generator. We propose two novel techniques to improve the software performance of these algorithms. We show how delayed modular reduction increases the efficiency of the LFSR feedback function, yielding performance gains for ZUC and thus both 128-EEA3 and 128-EIA3. We also show how to leverage carryless multiplication to evaluate the universal hash function making up the core of 128-EIA3. Our software implementation results on Qualcomm\'s Hexagon DSP architecture indicate significant performance gains when employing these techniques: up to roughly a 2-fold and 2.5-fold throughput improvement for 128-EEA3 and 128-EIA3, respectively.