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)
- 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
-
CC BY