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Best differential characteristic search of FEAL

  • Kazumaro Aoki
  • Kunio Kobayashi
  • Shiho Moriai
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1267)

Abstract

This paper presents the results of the best differential characteristic search of FEAL.

The search algorithm for the best differential characteristic (best linear expression) was already presented by Matsui, and improvements on this algorithm were presented by Moriai et al. We further improve the speed of the search algorithm. For example, the search time for the 7-round best differential characteristic of FEAL is reduced to about 10 minutes (Pentium/166 MHz), which is about 212.6 times faster than Matsui’s algorithm. Moreover, we determine all the best differential characteristics of FEAL for up to 32 rounds assuming all S-boxes are independent.

As a result, we confirm that the N-round (7≤N≤32) best differential characteristic probability of FEAL is 2−2N, which was found by Biham. For N=6, we find 6-round differential characteristics with a greater probability, 2−11, than that previously discovered, 2−12.

Keywords

Search Algorithm Search Pattern Block Cipher Differential Characteristic Bend Function 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

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Copyright information

© Springer-Verlag 1997

Authors and Affiliations

  • Kazumaro Aoki
    • 1
  • Kunio Kobayashi
    • 2
  • Shiho Moriai
    • 3
  1. 1.NTT LaboratoriesJapan
  2. 2.School of Science and EngineeringWaseda UniversityJapan
  3. 3.Information & Communication Security ProjectTelecommunications Advancement Organization of JapanJapan

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