Dakshita Khurana: How to Achieve Non-malleability in One or Two Rounds, or, A Knowledge Extraction Technique for Two Round Protocols
Date: Friday, June 16, 2017
Time: 10:30 AM to 12:00 PM Note: all times are in the Eastern Time Zone
Location: Hewlett, G882
Host: Vinod Vaikuntanathan
Contact: Deborah Goodwin, 617.324.7303, email@example.com
Speaker URL: None
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
Created by Deborah Goodwin at Wednesday, June 14, 2017 at 10:33 AM.