[QIP-Sem] MIT QIP Seminar Reminder

[QIP-Sem Mailing List]

This week's MIT QIP seminar will take place on Monday, February 23rd 
at 16:00 hours in MIT room 4-237, and features:


Zero-Knowledge Proofs Withstanding Quantum Attacks

by Dr. Louis Salvail (Computer Science, Univ. of Aarhus, Denmark)

ABSTRACT

The  concept of zero-knowledge (ZK) proof has become of fundamental 
importance in cryptography. However, in a setting where entities are 
modeled by quantum computers, classical arguments for proving ZK fail 
to hold. Specifically, in the quantum setting, the concept of 
rewinding is not generally applicable, and protocols that are 
classically proven to be ZK may be insecure. Moreover, known 
classical techniques that avoid rewinding have various shortcomings 
in the quantum setting.

In this talk, I shall introduce new techniques for building 
zero-knowledge protocols secure against quantum adversaries (QZK 
protocols). We will see how to obtain QZK proofs and  perfect QZK 
arguments for any NP language in the common reference string model. 
Underlying this is a general method to convert an important class of 
classical honest-verifier ZK (HVZK) proofs into "quantum" ZK (QZK) 
proofs that remain secure even under (active) quantum attacks. This 
leads to quite practical protocols if the underlying HVZK proof is 
efficient.

As part of the construction, we propose a general framework for 
building unconditionally hiding(trapdoor) string commitment schemes, 
secure against quantum attacks, as well as concrete instantiations 
based on specific (believed to be) hard problems. This is of 
independent interest, as these are the first  unconditionally hiding 
string commitment schemes withstanding quantum attacks.


Next week's feature: wim van Dam (CTP/MIT).
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