Paper 2021/126
Observer Attack on Stream Ciphers
Abstract
This paper proposes an internal state recovery attack on special class of stream generators called non-linear combiners and filter generators over finite fields consisting of linear feedback shift registers (LFSRs) and nonlinear functions combining internal states to form output stream. This attack utilizes the concept of an observer, well known in the theory of Linear Dynamical Systems. An observer is a special linear dynamical system which when fed with the output sequence of the stream generator as an input with arbitrary initial state, reconstructs the internal state of the generator in finite time. This attack is termed as observability attack and it is shown that the computations are of complexity
Note: Accepted in the proceedings of 25th International Symposium on Mathematical Theory of Networks and Systems (MTNS 2022)
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Preprint.
- Keywords
- Cryptanalysis Stream ciphers Koopman operator Observer theory
- Contact author(s)
-
ramachandran @ ee iitb ac in
vrs @ ee iitb ac in - History
- 2022-07-19: last of 2 revisions
- 2021-02-05: received
- See all versions
- Short URL
- https://ia.cr/2021/126
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2021/126, author = {Ramachandran Anantharaman and Virendra Sule}, title = {Observer Attack on Stream Ciphers}, howpublished = {Cryptology {ePrint} Archive, Paper 2021/126}, year = {2021}, url = {https://eprint.iacr.org/2021/126} }