International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: On Tweaking Luby-Rackoff Blockciphers

David Goldenberg
Susan Hohenberger
Moses Liskov
Elizabeth Crump Schwartz
Hakan Seyalioglu
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Abstract: Tweakable blockciphers, first formalized by Liskov, Rivest, and Wagner, are blockciphers with an additional input, the tweak, which allows for variability. An open problem proposed by Liskov et al. is how to construct tweakable blockciphers without using a pre-existing blockcipher. This problem has yet to receive any significant study. There are many natural questions in this area: is it significantly more effcient to incorporate a tweak directly? How do direct constructions compare to existing techniques? Are these direct constructions optimal and for what levels of security? How large of a tweak can be securely added? In this work, we address these questions for Luby-Rackoff blockciphers. We show that tweakable blockciphers can be created directly from Feistel ciphers, and in some cases show that direct constructions of tweakable blockciphers are more eĀ±cient than previously known constructions.
  title={On Tweaking Luby-Rackoff Blockciphers},
  booktitle={IACR Eprint archive},
  keywords={secret-key cryptography / block ciphers},
  note={Full version of paper in Asiacrypt 2007. 13762 received 6 Sep 2007},
  author={David Goldenberg and Susan Hohenberger and Moses Liskov and Elizabeth Crump Schwartz and Hakan Seyalioglu},