Dakshita Khurana: How to Achieve Non-malleability in One or Two Rounds, or, A Knowledge Extraction Technique for Two Round Protocols

Speaker: Dakshita Khurana

Date: Friday, June 16, 2017

Time: 10:30 AM to 12:00 PM Note: all times are in the Eastern Time Zone

Public: Yes

Location: Hewlett, G882

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Host: Vinod Vaikuntanathan

Contact: Deborah Goodwin, 617.324.7303, dlehto@csail.mit.edu

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Reminders to: seminars@csail.mit.edu, cis-seminars@csail.mit.edu

Reminder Subject: TALK: Dakshita Khurana: How to Achieve Non-malleability in One or Two Rounds, or, A Knowledge Extraction Technique for Two Round Protocols

Abstract: Knowledge extraction is an important technique central to several cryptographic protocols. Usually, protocols requiring knowledge extraction based on standard assumptions require at least three rounds of interaction.

In this talk, I will describe a new black-box knowledge extraction technique for two round protocols that only relies on sub-exponential DDH or QR or Nth residuosity. We use this extraction technique to obtain new protocols in the realm of non-malleable commitments and zero-knowledge, that were believed to be impossible so far.
- We obtain the first constructions of two-message non-malleable commitments satisfying the strong definition of non-malleability with respect to commitment.
- We also obtain one-round non-malleable commitments with respect to opening, which we use to obtain simple constructions of two round multi-party coin-tossing with simultaneous messages.
- We also construct two-message zero-knowledge with strong super-polynomial simulation. In particular, our protocol has a uniform simulator that runs in time less than the quality of zero-knowledge.

Joint work with Amit Sahai. Eprint: https://eprint.iacr.org/2017/291.pdf

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See other events that are part of the Cryptography and Information Seminar (CIS) 2017.

Created by Deborah Goodwin Email at Wednesday, June 14, 2017 at 10:33 AM.