Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Some Cryptanalytic Results on Lizard
 
research article

Some Cryptanalytic Results on Lizard

Banik, Subhadeep  
•
Isobe, Takanori
•
Cui, Tingting
Show more
2017
IACR Transactions on Symmetric Cryptology

Lizard is a lightweight stream cipher proposed by Hamann, Krause and Meier in IACR ToSC 2017. It has a Grain-like structure with two state registers of size 90 and 31 bits. The cipher uses a 120 bit secret key and a 64 bit IV. The authors claim that Lizard provides 80-bit security against key recovery attacks and a 60-bit security against distinguishing attacks. In this paper, we present an assortment of results and observations on Lizard. First, we show that by doing $2^58$ random trials it is possible to find a set of 2 64 triplets (K, IV 0 , IV 1 ) such that the Key-IV pairs (K, IV 0 ) and (K, IV 1 ) produce identical keystream bits. Second, we show that by performing only around 2 28 random trials it is possible to obtain $2^64$ Key-IV pairs (K 0 , IV 0 ) and (K 1 , IV 1 ) that produce identical keystream bits. Thereafter, we show that one can construct a distinguisher for Lizard based on IVs that produce shifted keystream sequences. The process takes around $2^{51.5}$ random IV encryptions (with encryption required to produce $2^{18}$ keystream bits) and around $2^{76.6}$ bits of memory. Next, we propose a key recovery attack on a version of Lizard with the number of initialization rounds reduced to 223 (out of 256) based on IV collisions. We then outline a method to extend our attack to 226 rounds. Our results do not affect the security claims of the designers.

  • Details
  • Metrics
Type
research article
DOI
10.13154/tosc.v2017.i4.82-98
Author(s)
Banik, Subhadeep  
Isobe, Takanori
Cui, Tingting
Guo, Jian
Date Issued

2017

Published in
IACR Transactions on Symmetric Cryptology
Volume

2017

Issue

4

Start page

82

End page

98

Editorial or Peer reviewed

REVIEWED

Written at

EPFL

EPFL units
LASEC  
Available on Infoscience
November 2, 2017
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/141733
Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés