International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

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

Authors:
Nicolas T. Courtois
Karsten Nohl
Sean O'Neil
Download:
URL: http://eprint.iacr.org/2008/166
Search ePrint
Search Google
Abstract: 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.
BibTeX
@misc{eprint-2008-17843,
  title={Algebraic Attacks on the Crypto-1 Stream Cipher in MiFare Classic and Oyster Cards},
  booktitle={IACR Eprint archive},
  keywords={secret-key cryptography / Mifare Crypto 1 algorithm, stream ciphers,  algebraic cryptanalysis, Boolean functions, Gröbner bases, SAT solvers},
  url={http://eprint.iacr.org/2008/166},
  note={ n.courtois@ucl.ac.uk 13983 received 13 Apr 2008, last revised 14 Apr 2008},
  author={Nicolas T. Courtois and Karsten Nohl and Sean O'Neil},
  year=2008
}