Improved Distinguishers on Stream Ciphers with Certain Weak Feedback Polynomials
Författare
Summary, in English
It is well known that fast correlation attacks can be very efficient if the feedback polynomial is of low weight. These feedback polynomials can be considered weak in the context of stream ciphers. This paper generalizes the class of weak feedback polynomials into polynomials were taps are located in several groups, possibly far apart. Low weight feedback polynomials are thus a special case of this class. For the general class it is shown that attacks can sometimes be very efficient even though the polynomials are of large weight. The main idea is to consider vectors of noise variables. It is shown how the complexity of a distinguishing attack can be efficiently computed and that the complexity is closely related to the minimum row distance of a generator matrix for a convolutional code. Moreover, theoretical results on the size of the vectors are given.
Avdelning/ar
Publiceringsår
2012
Språk
Engelska
Sidor
6183-6193
Publikation/Tidskrift/Serie
IEEE Transactions on Information Theory
Volym
58
Issue
9
Dokumenttyp
Artikel i tidskrift
Förlag
IEEE - Institute of Electrical and Electronics Engineers Inc.
Ämne
- Electrical Engineering, Electronic Engineering, Information Engineering
Nyckelord
- correlation attack
- LFSR
- stream cipher
- weak feedback polynomial
Status
Published
Forskningsgrupp
- Crypto and Security
ISBN/ISSN/Övrigt
- ISSN: 0018-9448