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Three Ways to Mount Distinguishing Attacks on Irregularly Clocked Stream Ciphers

Englund, Håkan LU and Johansson, Thomas LU (2006) In International Journal of Security and Networks 1(1/2). p.95-102
Abstract
Many stream ciphers use irregular clocking to introduce nonlinearity

to the keystream. We present three distinguishers on irregularly

clocked linear feedback shift registers.

The general idea used is to find suitable linear combinations of

keystream bits, here called samples, that are drawn from a

biased distribution. We describe how to place windows around the

estimated positions around members of the linear combinations, and very

efficiently create many samples with low computational complexity.

We also describe ideas based on constructing samples consisting of

vectors of bits (words) instead of single binary samples.

These vectors based methods... (More)
Many stream ciphers use irregular clocking to introduce nonlinearity

to the keystream. We present three distinguishers on irregularly

clocked linear feedback shift registers.

The general idea used is to find suitable linear combinations of

keystream bits, here called samples, that are drawn from a

biased distribution. We describe how to place windows around the

estimated positions around members of the linear combinations, and very

efficiently create many samples with low computational complexity.

We also describe ideas based on constructing samples consisting of

vectors of bits (words) instead of single binary samples.

These vectors based methods can distinguish the cipher using fewer

keystream bits but sometimes require a higher computational complexity. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
distinguishing attack, irregularly clocked LFSR
in
International Journal of Security and Networks
volume
1
issue
1/2
pages
95 - 102
publisher
Inderscience
external identifiers
  • scopus:72449209394
language
English
LU publication?
yes
id
685b3728-0939-455a-9ec8-1874458569c0 (old id 601588)
date added to LUP
2007-11-21 10:50:54
date last changed
2017-01-01 07:58:08
@article{685b3728-0939-455a-9ec8-1874458569c0,
  abstract     = {Many stream ciphers use irregular clocking to introduce nonlinearity<br/><br>
to the keystream. We present three distinguishers on irregularly<br/><br>
clocked linear feedback shift registers. <br/><br>
The general idea used is to find suitable linear combinations of<br/><br>
keystream bits, here called samples, that are drawn from a<br/><br>
biased distribution. We describe how to place windows around the<br/><br>
estimated positions around members of the linear combinations, and very<br/><br>
efficiently create many samples with low computational complexity. <br/><br>
We also describe ideas based on constructing samples consisting of<br/><br>
vectors of bits (words) instead of single binary samples. <br/><br>
These vectors based methods can distinguish the cipher using fewer<br/><br>
keystream bits but sometimes require a higher computational complexity.},
  author       = {Englund, Håkan and Johansson, Thomas},
  keyword      = {distinguishing attack,irregularly clocked LFSR},
  language     = {eng},
  number       = {1/2},
  pages        = {95--102},
  publisher    = {Inderscience},
  series       = {International Journal of Security and Networks},
  title        = {Three Ways to Mount Distinguishing Attacks on Irregularly Clocked Stream Ciphers},
  volume       = {1},
  year         = {2006},
}