Reference : Provable Security of (Tweakable) Block Ciphers Based on Substitution-Permutation Networks |
Scientific congresses, symposiums and conference proceedings : Paper published in a book | |||
Engineering, computing & technology : Computer science | |||
Security, Reliability and Trust | |||
http://hdl.handle.net/10993/42328 | |||
Provable Security of (Tweakable) Block Ciphers Based on Substitution-Permutation Networks | |
English | |
Cogliati, Benoît-Michel ![]() | |
Dodis, Yevgeniy ![]() | |
Katz, Jonathan ![]() | |
Lee, Jooyoung ![]() | |
Steinberger, John ![]() | |
Thiruvengadam, Aishwarya ![]() | |
Zhang, Zhe ![]() | |
2018 | |
Provable Security of (Tweakable) Block Ciphers Based on Substitution-Permutation Networks | |
Yes | |
CRYPTO 2018 | |
August 19-23, 2018 | |
[en] substitution-permutation networks ; tweakable block ciphers ; domain extension of block ciphers ; beyond-birthday-bound security | |
[en] Substitution-Permutation Networks (SPNs) refer to a family
of constructions which build a wn-bit block cipher from n-bit public permutations (often called S-boxes), which alternate keyless and “local” substitution steps utilizing such S-boxes, with keyed and “global” permu- tation steps which are non-cryptographic. Many widely deployed block ciphers are constructed based on the SPNs, but there are essentially no provable-security results about SPNs. In this work, we initiate a comprehensive study of the provable security of SPNs as (possibly tweakable) wn-bit block ciphers, when the underlying n-bit permutation is modeled as a public random permutation. When the permutation step is linear (which is the case for most existing designs), we show that 3 SPN rounds are necessary and sufficient for security. On the other hand, even 1-round SPNs can be secure when non-linearity is allowed. Moreover, 2-round non-linear SPNs can achieve “beyond- birthday” (up to 2 2n/3 adversarial queries) security, and, as the number of non-linear rounds increases, our bounds are meaningful for the number of queries approaching 2 n . Finally, our non-linear SPNs can be made tweakable by incorporating the tweak into the permutation layer, and provide good multi-user security. As an application, our construction can turn two public n-bit permuta- tions (or fixed-key block ciphers) into a tweakable block cipher working on wn-bit inputs, 6n-bit key and an n-bit tweak (for any w ≥ 2); the tweakable block cipher provides security up to 2 2n/3 adversarial queries in the random permutation model, while only requiring w calls to each permutation, and 3w field multiplications for each wn-bit input. | |
Researchers | |
http://hdl.handle.net/10993/42328 | |
© IACR 2018. This article is the final version submitted by the author(s) to the IACR and to Springer-Verlag on 2018-06-10. The version published by Springer-Verlag is available at 10.1007/978-3-319-96884-1\_24 | |
H2020 ; 644209 - HEAT - Homomorphic Encryption Applications and Technology |
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