Online Ciphers from Tweakable Blockciphers
Authors:
Phillip Rogaway and
Haibin Zhang
Abstract:
Online ciphers are deterministic length-preserving permutations
EK : ({0,1}n )+→({0, 1}n )+
where the i-th block of ciphertext
depends only on the first i blocks of plaintext. Definitions, constructions,
and applications for these objects were first given by Bellare, Boldyreva,
Knudsen, and Namprempre.We simplify and generalize their work, showing
that online ciphers are rather trivially constructed from tweakable
blockciphers, a notion of Liskov, Rivest, and Wagner. We go on to show
how to define and achieve online ciphers for settings in which messages
need not be a multiple of n bits.
References:
Proceedings of CT-RSA 2011
Full Version:
Conference version available in pdf