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Security Analysis of Michael: The IEEE 802.11i Message Integrity Code

  • Conference paper

Part of the Lecture Notes in Computer Science book series (LNCS,volume 3823)


The latest IEEE 802.11i uses a keyed hash function, called Michael, as the message integrity code. This paper describes some properties and weaknesses of Michael. We provide a necessary and sufficient condition for finding collisions of Michael. Our observation reveals that the collision status of Michael only depends on the second last block message and the output of the block function in the third last round. We show that Michael is not collision-free by providing a method to find collisions of this keyed hash function. Moreover, we develop a method to find fixed points of Michael. If the output of the block function in any round is equal to any of these fixed points, a packet forgery attack could be mounted against Michael. Since the Michael value is encrypted by RC4, the proposed packet forgery attack does not endanger the security of the whole TKIP system.


  • Medium Access Control
  • Advance Encryption Standard
  • Block Function
  • Collision Status
  • Forgery Attack

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.


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© 2005 Springer-Verlag Berlin Heidelberg

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Huang, J., Seberry, J., Susilo, W., Bunder, M. (2005). Security Analysis of Michael: The IEEE 802.11i Message Integrity Code. In: Enokido, T., Yan, L., Xiao, B., Kim, D., Dai, Y., Yang, L.T. (eds) Embedded and Ubiquitous Computing – EUC 2005 Workshops. EUC 2005. Lecture Notes in Computer Science, vol 3823. Springer, Berlin, Heidelberg.

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  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-30803-4

  • Online ISBN: 978-3-540-32296-2

  • eBook Packages: Computer ScienceComputer Science (R0)