Instruction Set Extensions for Cryptographic Applications

Instruction-set extension (ISE) has been widely studied as a means to improve the performance of microprocessor devices running cryptographic applications. It consists, essentially, in endowing an existing processor with a set of additional instructions that can be useful for speeding-up specific cryptographic computations. Recently, researchers became aware of the following: ”The efficiency of an implementation algorithm often depends heavily on the details of the target platform, e.g., on the instruction set or the pipeline of a processor. Hence, theoretical complexity measures, such as the bit complexity, can be misleading in practice” ([48]). In this chapter, we will analyze the implications of designing and deploying an instruction-set extension for a microprocessor, we will give details on existing research proposals for various cryptographic applications, highlighting the associated benefits and limitations, and we will show the ISEs that are available in some market products and proposed in research studies.