Maximizing the Potential of Custom RISC-V Vector Extensions for Speeding up SHA-3 Hash Functions

Huimin Li, Nele Mentens, Stjepan Picek

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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SHA-3 is considered to be one of the most secure standardized hash functions. It relies on the Keccak-f[1 600] permutation, which operates on an internal state of 1 600 bits, mostly represented as a 5 x 5 x 64-bit matrix. While existing implementations process the state sequentially in chunks of typically 32 or 64 bits, the Keccak-f[1 600] permutation can benefit a lot from speedup through parallelization. This paper is the first to explore the full potential of parallelization of Keccak-f[1 600] in RISC-V based processors through custom vector extensions on 32-bit and 64-bit architectures. We analyze the Keccak $\mathbf{f}[1 \ 600]$ permutation, composed of five different step mappings, and propose ten custom vector instructions to speed up the computation. We realize these extensions in a SIMD processor described in System Verilog. We compare the performance of our designs to existing architectures based on vectorized application-specific instruction set processors (ASIP). We show that our designs outperform all related work in throughput due to our carefully selected custom vector instructions.
Original languageEnglish
Title of host publicationProceedings of the 2023 Design, Automation & Test in Europe Conference & Exhibition (DATE)
Place of PublicationPiscataway
Number of pages6
ISBN (Print)979-8-3503-9624-9
Publication statusPublished - 2023
EventDATE 2023: Design, Automation & Test in Europe Conference & Exhibition - Antwerp, Belgium
Duration: 17 Apr 202319 Apr 2023


ConferenceDATE 2023
Internet address

Bibliographical note

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.


  • Keccak
  • SHA-3
  • Vector Extensions
  • SIMD Processor
  • RISC-V

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