International Association for Cryptologic Research

International Association
for Cryptologic Research


LIZARD - A Lightweight Stream Cipher for Power-constrained Devices

Matthias Hamann , University of Mannheim
Matthias Krause , University of Mannheim
Willi Meier , FH Nordwestschweiz
DOI: 10.13154/tosc.v2017.i1.45-79
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Abstract: Time-memory-data (TMD) tradeoff attacks limit the security level of many classical stream ciphers (like E0, A5/1, Trivium, Grain) to 1/2n, where n denotes the inner state length of the underlying keystream generator. In this paper, we present Lizard, a lightweight stream cipher for power-constrained devices like passive RFID tags. Its hardware efficiency results from combining a Grain-like design with the FP(1)-mode, a recently suggested construction principle for the state initialization of stream ciphers, which offers provable 2/3n-security against TMD tradeoff attacks aiming at key recovery. Lizard uses 120-bit keys, 64-bit IVs and has an inner state length of 121 bit. It is supposed to provide 80-bit security against key recovery attacks. Lizard allows to generate up to 218 keystream bits per key/IV pair, which would be sufficient for many existing communication scenarios like Bluetooth, WLAN or HTTPS.
  title={LIZARD - A Lightweight Stream Cipher for Power-constrained Devices},
  journal={IACR Trans. Symmetric Cryptol.},
  publisher={Ruhr-Universit├Ąt Bochum},
  volume={2017, Issue 1},
  author={Matthias Hamann and Matthias Krause and Willi Meier},