[Colloq] Debbie Cook - Director of IA Candidate - to talk on Sept. 5

[Rachel Kalweit]

Debra Cook will be joining us on Friday, September 5 at 10:30am in room 366 WVH to do a hiring talk. Debbie is a candidate for the Director of Information Assurance Program

Title: Constructions of Pseudorandom Permutations and Their Applications in
Symmetric Key Cryptography

Speaker: Debbie Cook (Bell Labs)

Joint work with Moti Yung (Google Inc. and Columbia University) and Angelos
Keromytis (Columbia University)

Abstract:
Various cryptographic algorithms used in practice, including block ciphers,
stream ciphers and modes of encryption, are heuristics in the sense that
they are not proven to be secure in general, but rather are proven to be
secure against specific attacks. However, there are underlying constructions
with provable security properties in theory that can serve as a basis for
practical algorithms. For example, the Feistel Network, proven by Luby and
Rackoff to be a pseudorandom permutation (PRP) and strong pseudorandom
permutation (SPRP) under certain conditions, has been used as a basis for
block cipher designs supporting fixed-length inputs. We discuss
constructions of PRPs and SPRPs for block ciphers and modes of encryption
that support variable-length blocks and multiple blocks. Among these are
Halevi and Rogaway's CMC mode of encryption, and Bellare and Rogaway's
Variable-Input Length Ciphers. More recently, the Elastic Network,
introduced by Cook, Yung and Keromytis, has been proposed as a construction
for creating variable-length block ciphers that results in the computational
workload being proportional to the input length. We show how the elastic
network allows any fixed-length block cipher to be converted to a
variable-length block cipher (an elastic block cipher). We provide an
overview of the security analysis for elastic block ciphers and describe an
implementation of an elastic version of AES. We also discuss applications of
elastic block ciphers, including database encryption and new modes of
encryption. Finally, we discuss proposals for how these constructions can be
utilized in the design of hash functions.

Host: Agnes Chan