Paper 2021/236

SNOW-Vi: an extreme performance variant of SNOW-V for lower grade CPUs

Patrik Ekdahl, Thomas Johansson, Alexander Maximov, and Jing Yang


SNOW 3G is a stream cipher used as one of the standard algorithms for data confidentiality and integrity protection over the air interface in the 3G and 4G mobile communication systems. SNOW-V is a recent new version that was proposed as a candidate for inclusion in the 5G standard. In this paper, we propose a faster variant of SNOW-V, called SNOW-Vi, that can reach the targeted speeds for 5G in a software implementation on a larger variety of CPU architectures. SNOW-Vi differs in the way how the LFSR is updated and also introduces a new location of the tap $T2$ for stronger security, while everything else is kept the same as in SNOW-V. The throughput in a software environment is increased by around 50\% in average, up to 92 Gbps. This makes the applicability of the cipher much wider and more use cases are covered. The security analyses previously done for SNOW-V are not affected in most aspects, and SNOW-Vi provides the same 256-bit security level as SNOW-V.

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. ACM WiSec 2021
SNOWStream Cipher5G Mobile System Security
Contact author(s)
alexander maximov @ ericsson com
2021-06-25: revised
2021-03-02: received
See all versions
Short URL
Creative Commons Attribution


      author = {Patrik Ekdahl and Thomas Johansson and Alexander Maximov and Jing Yang},
      title = {{SNOW}-Vi: an extreme performance variant of {SNOW}-V for lower grade {CPUs}},
      howpublished = {Cryptology ePrint Archive, Paper 2021/236},
      year = {2021},
      doi = {10.1145/3448300.3467829},
      note = {\url{}},
      url = {}
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