Paper 2013/728
Modified Alternating Step Generators
Robert Wicik and Tomasz Rachwalik
Abstract
Irregular clocking of feedback shift registers is a popular technique to improve parameters of keystream generators in stream ciphers. Another technique is to implement nonlinear functions. We join these techniques and propose Modified Alternating Step Generators built with linear and nonlinear feedback shift registers. Adequate nonlinear Boolean functions are used as feedbacks or as filtering functions of shift registers in order to increase complexity of sequences produced by individual registers and the whole generator. We investigate basic parameters of proposed keystream generators, such as period, linear complexity and randomness.
Note: Having nonlinear, maximal period registers, we tried to apply them in keystream generator - the ASG proposed by C. Günther. But NLFSRs we obtained are to short, so we propose other modified ASGs with nonlinear filtering, combining functions. Some properties of these generators were investigated in this paper. More work is needed to analyze their resistance to the cryptanalysis.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. Minor revision. Military Communications and Information Systems Conference, Saint Malo, France, 2013
- Keywords
- stream ciphersalternating step generatorfeedback shift registersperiod and linear complexityrandomness
- Contact author(s)
- r wicik @ wil waw pl
- History
- 2013-11-13: revised
- 2013-11-13: received
- See all versions
- Short URL
- https://ia.cr/2013/728
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2013/728,
author = {Robert Wicik and Tomasz Rachwalik},
title = {Modified Alternating Step Generators},
howpublished = {Cryptology {ePrint} Archive, Paper 2013/728},
year = {2013},
url = {https://eprint.iacr.org/2013/728}
}
