New results against the Mifare cipher

Peter Gutmann pgut001 at
Thu Apr 17 04:21:28 EDT 2008

  Algebraic Attacks on the Crypto-1 Stream Cipher in MiFare Classic and Oyster

  Nicolas T. Courtois and Karsten Nohl and Sean O'Neil

  MiFare Crypto 1 is a lightweight stream cipher used in London's Oyster card,
  Netherland's OV-Chipcard, US Boston's CharlieCard, and in numerous wireless
  access control and ticketing systems worldwide. Recently, researchers have
  been able to recover this algorithm by reverse engineering.

  We have examined MiFare from the point of view of the so called "algebraic
  attacks". We can recover the full 48-bit key of MiFare algorithm in 200
  seconds on a PC, given 1 known IV (from one single encryption).

  The security of this cipher is therefore close to zero. This is particularly
  shocking, given the fact that, according to the Dutch press, 1 billion of
  MiFare Classic chips are used worldwide, including in many governmental
  security systems.


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