Three Ways to Mount Distinguishing Attacks on Irregularly Clocked Stream Ciphers
Author
Summary, in English
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.
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.
Publishing year
2006
Language
English
Pages
95-102
Publication/Series
International Journal of Security and Networks
Volume
1
Issue
1/2
Document type
Journal article
Publisher
Inderscience Publishers
Topic
- Electrical Engineering, Electronic Engineering, Information Engineering
Keywords
- distinguishing attack
- irregularly clocked LFSR
Status
Published
Research group
- Informations- och kommunikationsteori