Digital Implementation of an Improved LTE Stream Cipher Snow-3G Based on Hyperchaotic PRNG

Abstract

SNOW-3G is a stream cipher used by the 3GPP standards as the core part of the confidentiality and integrity algorithms for UMTS and LTE networks. This paper proposes an enhancement of the regular SNOW-3G ciphering algorithm based on HC-PRNG. The proposed cipher scheme is based on hyperchaotic generator which is used as an additional layer to the SNOW-3G architecture to improve the randomness of its output keystream. The objective of this work is to achieve a high security strength of the regular SNOW-3G algorithm while maintaining its standardized properties. The originality of this new scheme is that it provides a good trade-off between good randomness properties, performance, and hardware resources. Numerical simulations, hardware digital implementation, and experimental results using Xilinx FPGA Virtex technology have demonstrated the feasibility and the efficiency of our secure solution while promising technique can be applied to secure the new generation mobile standards. Thorough analysis of statistical randomness is carried out demonstrating the improved statistical randomness properties of the new scheme compared to the standard SNOW-3G, while preserving its resistance against cryptanalytic attacks.

Optimized architecture for SNOW 3G

“…Reduction in propagation delay and chip area is possible in existing architectures [12][13][14][15][16]22], so the presented research work uses universal gates for CLA implementation and other techniques to minimize the number of gates required. Novel modulo CLA architecture over 2 32 uses following three architectures in multilevel CLA designs for performance improvement -4 bit CLA at LSB (to calculate S0 to S3) -4 bit CLA at middle stages (to calculate S4 to S27) -4 bit CLA at MSB (to calculate S28 to S31)…”

“…The total memory needed for the realization of two S-boxes is 8KB. Existing implementation [10][11][12][13][14][15][16][26][27][28][29] uses S-box architecture as shown in Figure 3. The four lookup tables of S1 i.e.…”

“…The use of these novel architectures minimizes hardware requirement as shown in the Figure 11. The comparison shows that the hardware resources used in the presented architectures are less than existing architectures [12][13][14][15][16]. The reduction in area is possible because S-box is designed using one lookup table in place of four lookup tables.…”

“…Optimized SNOW 3G architecture uses refined modulo CLA over 2 32 and refined S-box to for performance improvement. Hardware resources used by optimized SNOW 3G architecture are presented in Table 3 and Table 4 shows comparisons of hardware resources used by optimized SNOW 3G and existing architectures [12][13][14][15][16].…”

“…The presented work uses optimized architecture for SNOW 3G stream cipher. This architecture requires only 2K bytes of memory for implementation of S-box in place of 8K bytes of memory required for the existing SNOW 3G architectures [10][11][12][13][14][15][16]. The paper is arranged in the following sections.…”