A practical attack on KeeLoq

Sebastiaan Indesteege; Nathan Keller; Orr Dunkelman; Eli Biham; Bart Preneel

doi:10.1007/978-3-540-78967-3_1

A practical attack on KeeLoq

Sebastiaan Indesteege, Nathan Keller, Orr Dunkelman, Eli Biham, Bart Preneel

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

80 Scopus citations

Abstract

KeeLoq is a lightweight block cipher with a 32-bit block size and a 64-bit key. Despite its short key size, it is widely used in remote keyless entry systems and other wireless authentication applications. For example, authentication protocols based on KeeLoq are supposedly used by various car manufacturers in anti-theft mechanisms. This paper presents a practical key recovery attack against KeeLoq that requires 2¹⁶ known plaintexts and has a time complexity of 2^44.5 KeeLoq encryptions. It is based on the slide attack and a novel approach to meet-in-the-middle attacks. The fully implemented attack requires 65 minutes to obtain the required data and 7.8 days of calculations on 64 CPU cores. A variant which requires 2¹⁶ chosen plaintexts needs only 3.4 days on 64 CPU cores. Using only 10 000 euro, an attacker can purchase a cluster of 50 dual core computers that will find the secret key in about two days. We investigated the way KeeLoq is intended to be used in practice and conclude that our attack can be used to subvert the security of real systems. An attacker can acquire chosen plaintexts in practice, and one of the two suggested key derivation schemes for KeeLoq allows to recover the master secret from a single key.

Original language	English
Title of host publication	Advances in Cryptology - EUROCRYPT 2008 - 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings
Pages	1-18
Number of pages	18
DOIs	https://doi.org/10.1007/978-3-540-78967-3_1
State	Published - 2008
Externally published	Yes
Event	27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2008 - Istanbul, Turkey Duration: 13 Apr 2008 → 17 Apr 2008

Publication series

Name	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume	4965 LNCS
ISSN (Print)	0302-9743
ISSN (Electronic)	1611-3349

Conference

Conference	27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2008
Country/Territory	Turkey
City	Istanbul
Period	13/04/08 → 17/04/08

Bibliographical note

Funding Information:
This work was supported in part by the Concerted Research Action (GOA) Ambiorics 2005/11 of the Flemish Government, by the IAP Programme P6/26 BCRYPT of the Belgian State (Belgian Science Policy), and in part by the European Commission through the IST Programme under Contract IST-2002-507932 ECRYPT.

Funding

This work was supported in part by the Concerted Research Action (GOA) Ambiorics 2005/11 of the Flemish Government, by the IAP Programme P6/26 BCRYPT of the Belgian State (Belgian Science Policy), and in part by the European Commission through the IST Programme under Contract IST-2002-507932 ECRYPT.

Funders	Funder number
European Commission	IST-2002-507932 ECRYPT
Vlaamse regering

Keywords

Block ciphers
Cryptanalysis
KeeLoq
Meet-in-the-middle attacks
Slide attacks

Access to Document

10.1007/978-3-540-78967-3_1

Cite this

Indesteege, S., Keller, N., Dunkelman, O., Biham, E., & Preneel, B. (2008). A practical attack on KeeLoq. In Advances in Cryptology - EUROCRYPT 2008 - 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings (pp. 1-18). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 4965 LNCS). https://doi.org/10.1007/978-3-540-78967-3_1

Indesteege, Sebastiaan ; Keller, Nathan ; Dunkelman, Orr et al. / A practical attack on KeeLoq. Advances in Cryptology - EUROCRYPT 2008 - 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings. 2008. pp. 1-18 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)).

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Indesteege, S, Keller, N, Dunkelman, O, Biham, E & Preneel, B 2008, A practical attack on KeeLoq. in Advances in Cryptology - EUROCRYPT 2008 - 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 4965 LNCS, pp. 1-18, 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2008, Istanbul, Turkey, 13/04/08. https://doi.org/10.1007/978-3-540-78967-3_1

A practical attack on KeeLoq. / Indesteege, Sebastiaan; Keller, Nathan; Dunkelman, Orr et al.
Advances in Cryptology - EUROCRYPT 2008 - 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings. 2008. p. 1-18 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 4965 LNCS).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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KW - Meet-in-the-middle attacks

KW - Slide attacks

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Indesteege S, Keller N, Dunkelman O, Biham E, Preneel B. A practical attack on KeeLoq. In Advances in Cryptology - EUROCRYPT 2008 - 27th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings. 2008. p. 1-18. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)). doi: 10.1007/978-3-540-78967-3_1

A practical attack on KeeLoq

Abstract

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Bibliographical note

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Keywords

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