Cryptographic Security of KeeLoq

page maintained by Nicolas T. Courtois

KeeLoq is a block cipher used in wireless devices that unlock the doors and alarms in cars manufactured by Chrysler, Daewoo, Fiat, GM, Honda, Jaguar, Toyota, Volvo, Volkswagen, etc. It is used by millions of people every day. Until now, algebraic attacks on block ciphers did not yield interesting results and most researchers seriously doubted if any block cipher would ever be broken by such attacks.
Combination of algebraic attacks and periodic (sliding) properties of KeeLoq allows to design many interesting attacks.
KeeLoq have been sold in 1995 for 10 million dollars.

Main References on KeeLoq.

Some links:
Algebraic attacks on block ciphers and AES

Algebraic attacks applied to stream ciphers

Maintained by Nicolas T. Courtois
Last updated on 17th of February2008.