GTACS

A Greater Tel-Aviv Area Seminar

David Xiao@TAU on Languages with Zero-Knowledge PCP's are in SZK

Probabilistically Checkable Proofs (PCPs) allow a verifier
to check the validity of a proof by querying very few random
positions in the proof string. Zero Knowledge (ZK) Proofs allow a
prover to convince a verifier of a statement without revealing any
information beyond the validity of the statement. We study for what
class of languages it is possible to achieve both, namely to build
ZK-PCPs, where additionally we require that the proof be generated

18/04/2013 - 11:00

Pavel Hubacek @ BIU on Limits on the Power of Cryptographic Cheap Talk

We revisit the question of whether cryptographic protocols can replace correlated equilibria mediators in two-player games. This problem was first addressed by Dodis, Halevi and Rabin (CRYPTO 2000), who suggested replacing the mediator with a secure protocol and proved that their solution is stable in the Nash equilibrium (NE) sense, provided that the players are computationally bounded.

25/04/2013 - 14:00

Nir Bitansky @ BIU on On the Impossibility of Approximate Obfuscation and Applications to Resettable Cryptography

The traditional notion of program obfuscation requires that an obfuscation P' of a program P computes the exact same function as P, but beyond that, the code of P' should not leak any information about P. This strong notion of virtual black-box security was shown by Barak et al. (CRYPTO 2001) to be impossible to achieve, for certain unobfuscatable function families.

18/04/2013 - 14:00