A high‐speed and low‐latency hardware implementation of RC4 cryptographic algorithm

Abstract

In this letter, a high‐speed and low‐latency Ron Rivest‐4 (RC4) encryption algorithm is designed based on SMIC 14 nm process. Since the key issue of limiting the throughput of RC4 encryption algorithm is the swapping operation of S‐box, this proposed design is capable of achieving four swapping operations of S‐box within a clock cycle by utilizing fully combinational logic designs and advanced computations. All 256 swapping operations of key scheduling algorithm (KSA) can be done in 64 clock cycles. Moreover, the novel design greatly improves the encryption efficiency of RC4 since each clock cycle offers 4 bytes of key stream. The whole area can be further optimized by reusing the existing modules, and a lightweight countermeasure is embedded into the RC4 design to break the correlation between the processed data and power dissipation against differential power analysis (DPA) attacks. Finally, the whole design is assessed by the SMIC 14 nm process design kits (PDK). The corresponding clock frequency, throughput, area, and latency, respectively, are achieved as 1 GHz, 32 Gbps, 51,596  m², and 74 clock cycles.