Some instant- and practical-time related-key attacks on KTANTAN32/48/64
(2012) Selected Areas in Cryptography In Lecture Notes in Computer Science 7118. p.213-229- Abstract
- The hardware-attractive block cipher family KTANTAN was studied by Bogdanov and Rechberger who identified flaws in the key schedule and gave a meet-in-the-middle attack. We revisit their result before investigating how to exploit the weakest key bits. We then develop several related-key attacks, e.g., one on KTANTAN32 which finds 28 key bits in time equivalent to $2^{3.0}$ calls to the full KTANTAN32 encryption. The main result is a related-key attack requiring $2^{28.44}$ time (half a minute on a current CPU) to recover the full 80-bit key. For KTANTAN48, we find three key bits in the time of one encryption, and give several other attacks, including full key recovery. For KTANTAN64, the attacks are only slightly more expensive, requiring... (More)
- The hardware-attractive block cipher family KTANTAN was studied by Bogdanov and Rechberger who identified flaws in the key schedule and gave a meet-in-the-middle attack. We revisit their result before investigating how to exploit the weakest key bits. We then develop several related-key attacks, e.g., one on KTANTAN32 which finds 28 key bits in time equivalent to $2^{3.0}$ calls to the full KTANTAN32 encryption. The main result is a related-key attack requiring $2^{28.44}$ time (half a minute on a current CPU) to recover the full 80-bit key. For KTANTAN48, we find three key bits in the time of one encryption, and give several other attacks, including full key recovery. For KTANTAN64, the attacks are only slightly more expensive, requiring $2^{10.71}$ time to find 38 key bits, and $2^{32.28}$ for the entire key. For all attacks, the requirements on related-key material are modest as in the forward and backward directions, we only need to flip a single key bit. All attacks succeed with probability one. Our attacks directly contradict the designers' claims. We discuss why this is, and what can be learnt from this. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/2296383
- author
- Ågren, Martin LU
- organization
- publishing date
- 2012
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- keywords
- cryptanalysis, related key, block cipher, key schedule, lightweight cipher, key-recovery
- host publication
- Selected Areas in Cryptography : 18th International Workshop, SAC 2011, Toronto, ON, Canada, August 11-12, 2011, Revised Selected Papers - 18th International Workshop, SAC 2011, Toronto, ON, Canada, August 11-12, 2011, Revised Selected Papers
- series title
- Lecture Notes in Computer Science
- volume
- 7118
- pages
- 213 - 229
- publisher
- Springer
- conference name
- Selected Areas in Cryptography
- conference location
- Toronto, Canada
- conference dates
- 2011-08-10 - 2011-08-12
- external identifiers
-
- scopus:84857758140
- ISSN
- 1611-3349
- 0302-9743
- ISBN
- 978-3-642-28496-0
- 978-3-642-28495-3
- DOI
- 10.1007/978-3-642-28496-0_13
- project
- EIT_HSWC:Coding Coding, modulation, security and their implementation
- language
- English
- LU publication?
- yes
- id
- 324ae4fb-190f-4004-8569-5ce19514a550 (old id 2296383)
- date added to LUP
- 2016-04-04 10:51:30
- date last changed
- 2024-01-12 22:02:18
@inbook{324ae4fb-190f-4004-8569-5ce19514a550, abstract = {{The hardware-attractive block cipher family KTANTAN was studied by Bogdanov and Rechberger who identified flaws in the key schedule and gave a meet-in-the-middle attack. We revisit their result before investigating how to exploit the weakest key bits. We then develop several related-key attacks, e.g., one on KTANTAN32 which finds 28 key bits in time equivalent to $2^{3.0}$ calls to the full KTANTAN32 encryption. The main result is a related-key attack requiring $2^{28.44}$ time (half a minute on a current CPU) to recover the full 80-bit key. For KTANTAN48, we find three key bits in the time of one encryption, and give several other attacks, including full key recovery. For KTANTAN64, the attacks are only slightly more expensive, requiring $2^{10.71}$ time to find 38 key bits, and $2^{32.28}$ for the entire key. For all attacks, the requirements on related-key material are modest as in the forward and backward directions, we only need to flip a single key bit. All attacks succeed with probability one. Our attacks directly contradict the designers' claims. We discuss why this is, and what can be learnt from this.}}, author = {{Ågren, Martin}}, booktitle = {{Selected Areas in Cryptography : 18th International Workshop, SAC 2011, Toronto, ON, Canada, August 11-12, 2011, Revised Selected Papers}}, isbn = {{978-3-642-28496-0}}, issn = {{1611-3349}}, keywords = {{cryptanalysis; related key; block cipher; key schedule; lightweight cipher; key-recovery}}, language = {{eng}}, pages = {{213--229}}, publisher = {{Springer}}, series = {{Lecture Notes in Computer Science}}, title = {{Some instant- and practical-time related-key attacks on KTANTAN32/48/64}}, url = {{https://lup.lub.lu.se/search/files/5637670/2296435.pdf}}, doi = {{10.1007/978-3-642-28496-0_13}}, volume = {{7118}}, year = {{2012}}, }