Paper 2022/1603

Slid Pairs of the Fruit-80 Stream Cipher

Pang Kok An, Universiti Teknikal Malaysia Melaka
Shekh Faisal Abdul-Latip, Universiti Teknikal Malaysia Melaka
Hazlin Abdul Rani, Cybersecurity Malaysia

Fruit is a small-state stream cipher designed for securing communications among resource-constrained devices. The design of Fruit was first known to the public in 2016. It was later improved as Fruit-80 in 2018 and becomes the latest and final version among all versions of the Fruit stream ciphers. In this paper, we analyze the Fruit-80 stream cipher. We found that Fruit-80 generates identical keystreams from certain two distinct pairs of key and IV. Such pair of key and IV pairs is known as a slid pair. Moreover, we discover that when two pairs of key and IV fulfill specific characteristics, they will generate identical keystreams. This shows that slid pairs do not always exist arbitrarily in Fruit-80. We define specific rules which are equivalent to the characteristics. Using the defined rules, we are able to automate the searching process using an MILP solver, which makes searching of the slid pairs trivial.

Available format(s)
Attacks and cryptanalysis
Publication info
Published elsewhere. International Journal of Communication Networks and Information Security
Fruit-80 stream ciphers slid pairs cryptanalysis
Contact author(s)
pangkokan @ gmail com
dr shekhfaisal @ gmail com
hazlin @ cybersecurity my
2022-11-21: approved
2022-11-17: received
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      author = {Pang Kok An and Shekh Faisal Abdul-Latip and Hazlin Abdul Rani},
      title = {Slid Pairs of the Fruit-80 Stream Cipher},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1603},
      year = {2022},
      note = {\url{}},
      url = {}
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