Generalization and extension of XEX* mode

Kazuhiko Minematsu*, Toshiyasu Matsushima

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


This paper describes an extension of XEX* mode, which is a method to convert a block cipher into a tagged tweakable block cipher, a notion introduced by Rogaway in 2004 as an extension of the tweakable block cipher by Liskov et al. Our extension attaches an additional encryption function to the original XEX*, which has some limitation but is slightly faster than the encryption implemented by XEX*. We prove our scheme's security in a general form, where the offset function, a key component of our construction, is not restricted to the one used by XEX*. We also provide some applications of our result, in particular to OCB 2.0, an authenticated encryption based on XEX*.

Original languageEnglish
Pages (from-to)517-524
Number of pages8
JournalIEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Issue number2
Publication statusPublished - 2009 Feb


  • OCB 2.0
  • Tweakable block cipher
  • XEX

ASJC Scopus subject areas

  • Signal Processing
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering
  • Applied Mathematics


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