Design of configurable LFSR instructions targeted at stream cipher processing

Abstract

By analyzing the operation characteristic of LFSRs in many public stream cipher algorithms and its bottleneck realized by general processor, several configurable specific instructions are proposed in this paper, which can neatly execute LFSR computing operation in parallel with high performance. The LFSR instructions brought out can sustain different operation data widths, different operating model. Instruction level parallelism based on VLIW system structure and instruction inner parallelism by operating several steps at one time are exploited too. The configurable instructions can be used as an important accelerated way in special processing for stream cipher.