The design of scalar AES Instruction Set Extensions for RISC-V

Ben Marshall*, G. Richard Newell, Daniel Page, Saarinen Markku-Juhani O., Claire Wolf

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)


Secure, efficient execution of AES is an essential requirement on most
computing platforms. Dedicated Instruction Set Extensions (ISEs) are often included for this purpose. RISC-V is a (relatively) new ISA that lacks such a standardised ISE. We survey the state-of-the-art industrial and academic ISEs for AES, implement and evaluate five different ISEs, one of which is novel. We recommend separate ISEs for 32 and 64-bit base architectures, with measured performance improvements for an AES-128 block encryption of 4× and 10× with a hardware cost of 1.1K and 8.2K gates respectivley, when compared to a software-only implementation based on use of T-tables. We also explore how the proposed standard bit-manipulation extension to RISC-V can be harnessed for efficient implementation of AES-GCM. Our work supports the ongoing RISC-V cryptography extension standardisation process.
Original languageEnglish
JournalIACR Transactions on Cryptographic Hardware and Embedded Systems (TCHES)
Publication statusAccepted/In press - 15 Sep 2020

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