The optimal key estimation of stream ciphers and its approximation algorithm based on a probabilistic inference

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

A stream cipher is an important class of encryption algorithms. Its safety depends on the structure of the pseudorandom number generator used. There are various types of pseudo-random number generators in existence, and attack algorithms used on them have been studied individually. In this paper, we express the problem of attacks on a general stream cipher as a probabilistic inference problem, and formulate the optimal key estimation. We also propose a unified framework of attack algorithms that can be applied to a wide variety of stream ciphers. The optimal key estimation, however, has computational complexity. To reduce the complexity, an approximation algorithm based on a probabilistic inference is proposed. We also describe some attack algorithms used on practical pseudorandom number generators. Finally, the proposed algorithm is evaluated by through a computer simulation.

Original languageEnglish
Title of host publication2012 International Symposium on Information Theory and Its Applications, ISITA 2012
Pages531-535
Number of pages5
Publication statusPublished - 2012 Dec 1
Event2012 International Symposium on Information Theory and Its Applications, ISITA 2012 - Honolulu, HI, United States
Duration: 2012 Oct 282012 Oct 31

Publication series

Name2012 International Symposium on Information Theory and Its Applications, ISITA 2012

Conference

Conference2012 International Symposium on Information Theory and Its Applications, ISITA 2012
CountryUnited States
CityHonolulu, HI
Period12/10/2812/10/31

ASJC Scopus subject areas

  • Computer Science Applications
  • Information Systems

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  • Cite this

    Iikubo, Y., Horii, S., & Matsushima, T. (2012). The optimal key estimation of stream ciphers and its approximation algorithm based on a probabilistic inference. In 2012 International Symposium on Information Theory and Its Applications, ISITA 2012 (pp. 531-535). [6400993] (2012 International Symposium on Information Theory and Its Applications, ISITA 2012).