Building blockcipher from tweakable blockcipher: Extending FSE 2009 proposal

Abstract

This paper extends the provably-secure blockcipher construction proposed at FSE 2009 by Minematsu. Unlike the classical Luby-Rackoff cipher and its variants, the scheme is based on tweakable blockciphers. An advantage of the scheme is that it provides the beyond-birthday-bound security quite efficiently. While FSE 2009 proposal was the case of building a 2n-bit blockcipher using an n-bit tweakable blockcipher, we extend it to shorter and longer block lengths than 2n bits, keeping the security of beyond the birthday bound. © 2011 Springer-Verlag.