Cryptology ePrint Archive: Report 2013/759

Vectorization of ChaCha Stream Cipher

Martin Goll and Shay Gueron

Abstract: This paper describes software optimization for the stream Cipher ChaCha. We leverage the wide vectorization capabilities of the new AVX2 architecture, to speed up ChaCha encryption (and decryption) on the latest x86_64 processors. In addition, we show how to apply vectorization for the future AVX512 architecture, and get further speedup. This leads to significant performance gains. For example, on the latest Intel Haswell microarchitecture, our AVX2 implementation performs at 1.43 cycles per byte (on a 4KB message), which is ~2x faster than the current implementation in the Chromium project.

Category / Keywords: implementation /

Date: received 17 Nov 2013, last revised 22 Nov 2013

Contact author: shay at math haifa ac il

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Version: 20131122:103413 (All versions of this report)

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