[Colloq] Thesis Proposal: "New Proof Techniques for Adaptive Security" | Speaker: Zahra Jafargholi | Date: Thursday, April 28th Time: 3:30pm-4:30pm Location: 366WVH

[Walker, Lashauna]

Title: New Proof Techniques for Adaptive Security
Speaker: Zahra Jafargholi
Date: Thursday, April 28th
Time: 3:30pm-4:30pm
Location: 366WVH


Title: New Proof Techniques for Adaptive Security

Abstract:

Selective security refers to the case where the attacker decides on some parameters of the attack before the attack even begins. In contrast, adaptive security refers to the case where the attacker can make decisions throughout the course of the attack. Therefore these decisions can depend on the information the attacker receives during the attack. One can use complexity-leveraging to reduce the problem of proving adaptive security to proving selective security. This technique which involves guessing the decisions the attacker makes during the attack, leads to an exponential loss in security reduction. Here we look at two settings, where we prove adaptive security from scratch - without reducing to selective security. The first problem, Generalized Selective Decryption (GSD) Game, captures security requirements of Broadcast and Multicast Encryption protocols. We give an analysis of the system that proves GSDG is adaptively secure with only a quasi-polynomial loss in the security reduction. In study of the second problem, Adaptively Secure Garbling Schemes, we devise a new garbling scheme that has Yao's garbling scheme at heart. Our adaptively secure garbling scheme has a garbled input of length proportional to the circuit's width. This is a considerable improvement over the previous schemes where the garbled input grew with the size of the entire circuit. We propose to study the techniques used. Is it possible to generalize the techniques and use them in different setting? What separate the two seemingly related techniques? Finally, we propose using the new techniques to analyze adaptive security of Yao's garbling scheme.

Committee:
Daniel Wichs (Advisor)
Rajmohan Rajaraman
Jonathan Ullman
Vinod Vaikuntanathan (MIT)

Proposal Web Page:
http://www.ccs.neu.edu/home/zahra/thesiscommittee.html



Thank You.

LaShauna Walker
Events and Administrative Specialist
College of Computer and Information Science
Northeastern University
617-373-2763
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