Paper 2008/369

New Directions in Cryptanalysis of Self-Synchronizing Stream Ciphers

Shahram Khazaei and Willi Meier

Abstract

In cryptology we commonly face the problem of finding an unknown key K from the output of an easily computable keyed function F(C,K) where the attacker has the power to choose the public variable C. In this work we focus on self-synchronizing stream ciphers. First we show how to model these primitives in the above-mentioned general problem by relating appropriate functions F to the underlying ciphers. Then we apply the recently proposed framework presented at AfricaCrypt’08 by Fischer et. al. for dealing with this kind of problems to the proposed T-function based self-synchronizing stream cipher by Klimov and Shamir at FSE’05 and show how to deduce some non-trivial information about the key. We also open a new window for answering a crucial question raised by Fischer et. al. regarding the problem of finding weak IV bits which is essential for their attack.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Published elsewhere. Unknown where it was published
Keywords
Self-synchronizing Stream CiphersT-functionsKey Recovery.
Contact author(s)
shahram khazaei @ gmail com
History
2008-10-04: revised
2008-08-27: received
See all versions
Short URL
https://ia.cr/2008/369
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2008/369,
      author = {Shahram Khazaei and Willi Meier},
      title = {New Directions in Cryptanalysis of Self-Synchronizing Stream Ciphers},
      howpublished = {Cryptology ePrint Archive, Paper 2008/369},
      year = {2008},
      note = {\url{https://eprint.iacr.org/2008/369}},
      url = {https://eprint.iacr.org/2008/369}
}
Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.