Collision Attacks on Hash Functions Using Linearization of Compress Function

Kazemi, Ehsan | 2010

564 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40697 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Aref, Mohammad Reza; Eghlidos, Taraneh
  7. Abstract:
  8. Collision attack is one of the usual attacks in cryptanalysis of hash functions. One method for applying this attack is linear approximation of equivalent compress function. Finding collisions for linearized compress function, having low Hamming weight, with a large probability could provide collisions for the main compress function. For this purpose, the problem of finding collision for used compress function is modeled by that of the linearized one, having low Hamming weight differences with a large probability. The problem of finding collisions with low Hamming weight differences is equivalent to the problem of finding codewords with low Hamming weights in linear binary code. Canteaut and Chabaud introduced a method for finding codewords with low Hamming weight. In this thesis we improve this method by modifying their algorithm by two ideas. Besides, using a M-algorithm we introduce a method for solving the problem with much lower computational complexity and relatively more efficiency. A combination of these two attack models is studied as well. We introduce an efficient non-deterministic method to analyze SHA-1 and CubeHash. This new method has advantage over previous methods for its lower computational complexity.
  9. Keywords:
  10. Hash Function ; Collision Attack ; Compress Function ; Linear Code ; Code Word ; Hamming Weight

 Digital Object List

  • محتواي پايان نامه
  •   view