The Foundations of Applied Cryptography

The pervasive adoption of cryptography makes it imperative to assess
when proposed solutions are secure, and when they are not. This talk
will explain that proving meaningful security guarantees for practical
cryptography often requires new and deep theoretical advances. I will
showcase three examples from my recent and ongoing research.

First, I will show that the strongest known provable guarantees for
common designs of block ciphers, the fundamental atomic building
blocks of cryptography, follow from new general information-theoretic
techniques I have developed.

Second, I will introduce a comprehensive theory of so-called
multi-user attacks, which aims in particular at measuring security
under Internet-scale deployment, and use it to validate existing and
upcoming cryptographic standards.

Finally, I will present proofs of best-possible lower bounds on
space-time trade-offs that validate in-use mechanisms to protect
passwords from attackers with access to special-purpose hardware, such
as GPUs and ASICs.

Stefano Tessaro is an Assistant Professor of Computer Science at UC
Santa Barbara, where he holds the Glen and Susanne Culler Chair. He
received his PhD from ETH Zurich in 2010, and held postdoctoral
positions at UC San Diego and MIT. His research interests span a wide
range of topics across cryptography and its applications. He has
received the Sloan Fellowship, the NSF CAREER Award, the Hellman
Fellowship, the best paper award at EUROCRYPT 2017, and the best
student paper award at TCC 2011.