SPEAKER:
Tal Rabin
IBM T. J. Watson

TITLE: 
Information-Theoretically Secure Protocols and 
Security Under Composition

ABSTRACT:

We investigate the question of whether security of protocols in
the information-theoretic setting (where the adversary is
computationally unbounded) implies the security of these protocols
under concurrent composition. This question is motivated by the
folklore that all known protocols that are secure in the
information-theoretic setting are indeed secure under concurrent
composition. We provide answers to this question for a number of
different settings (i.e., considering  perfect versus statistical
security, and concurrent composition with adaptive versus fixed
inputs). Our results enhance the understanding of what is
necessary for obtaining security under composition, as well as
providing tools (i.e., composition theorems) that can be used for
proving the security of protocols under composition while
considering only the standard stand-alone definitions of security.

Joint work with: Eyal Kushilevitz and Yehuda Lindell