Chethan Kamath

简介

2024- Assistant Professor at IIT Bombay 2021-2023 Post-doc at Tel Aviv University, hosted by Nir Bitansky and Omer Paneth I was supported by an Azrieli fellowship 2020-21 Post-doc at Charles University, hosted by Pavel Hubáček 2020 Post-doc at Northeastern university, hosted by Daniel Wichs 2014-2020 PhD from IST Austria, under the supervision of Krzysztof Pietrzak My PhD thesis was titled On the Average-Case Hardness of Total Search Problems. 2010-2013 Master's in CS from IISc Bangalore, under the supervision of Sanjit Chatterjee My master's thesis was titled Constructing Provably Secure Identity-Based Signature Schemes 2005-2009 Bachelor's in CS from University of Kerala (at TKM College of Engineering, Kollam). SHORT-TERM VISITS Simons Institute - Summer 2015 FACT Center - Summer 2017, h

代表成果

• Titan: Efficient Polynomial Commitments from IOPs over Groups with Ravi Prakash, Samipa Samanta, Sruthi Sekar and Nitin Singh CCS 2026, to appear [+] Synopsis [↗] Paper [↗] Code Problem: Polynomial Commitment Scheme (PCS) is a key ingredient to constructing efficient SNARKs. While hash-based PCSs (e.g., WHIR) have low prover and verifier complexity, their proof size is usually large. On the other hand, pairing-based SNARKs (e.g., Dory) have short proofs, but their prover and verifier complexity is high. Can we get a PCS that is the best of both worlds? Result: In this work, we propose Titan which achieves this.
• Problem: Polynomial Commitment Scheme (PCS) is a key ingredient to constructing efficient SNARKs. While hash-based PCSs (e.g., WHIR) have low prover and verifier complexity, their proof size is usually large. On the other hand, pairing-based SNARKs (e.g., Dory) have short proofs, but their prover and verifier complexity is high. Can we get a PCS that is the best of both worlds?
• Result: In this work, we propose Titan which achieves this.
• Separating Verifiable Delay Functions and Time-Lock Puzzles with Hamza Abusalah, Nivesh Aggarwal, Karen Azari, and Maximilian von Consbruch Eurocrypt 2026 [+] Synopsis [↗] Paper [↓] Slides by Max and Nivesh Problem: We continue with the problem posed in [26], where we showed that a weak form of VDF can be constructed from TLP using heavy machinery. Result: In this work, we show that (oracle-aided) VDFs cannot be constructed from TLPs and vice versa, and thus the limitations of [26] is inherent. To this end, we rely on the techniques from [27].
• Problem: We continue with the problem posed in [26], where we showed that a weak form of VDF can be constructed from TLP using heavy machinery.
• Result: In this work, we show that (oracle-aided) VDFs cannot be constructed from TLPs and vice versa, and thus the limitations of [26] is inherent. To this end, we rely on the techniques from [27].
• Impossibility of VDFs in the ROM: The Complete Picture with Hamza Abusalah, Karen Azari, Erkan Tairi and Maximilian von Consbruch Eurocrypt 2026 [+] Synopsis [↗] Paper [↓] Slides [↓] Slides by Max Problem: Can Verifiable Delay Function (VDF) be constructed in the Random-Oracle Model) (ROM)? Result: Prior works [MSW20,GRY25] ruled out ROM-based computationally-unique VDFs with public setup. We complete the picture set forth by these works by ruling out ROM-based computationally-unique VDFs even with expensive private setup.
• Problem: Can Verifiable Delay Function (VDF) be constructed in the Random-Oracle Model) (ROM)?
• Result: Prior works [MSW20,GRY25] ruled out ROM-based computationally-unique VDFs with public setup. We complete the picture set forth by these works by ruling out ROM-based computationally-unique VDFs even with expensive private setup.
• On Verifiable Delay Functions from Time-Lock Puzzles with Hamza Abusalah, Karen Azari, Dario Fiore and Erkan Tairi PKC 2026 [+] Synopsis [↗] Paper [↓] Slides by Erkan Problem: Time-Lock Puzzles (TLPs) and verifiable delay functions (VDFs) are two central objects in timed cryptography. Constructions of TLP and VDF out there show superficial similarities: e.g., Pietrzak's and Wesolowski's constructions of VDF are essentially the Rivest-Shamir-Wagner TLP made publicly-verifiable. This begs the natural question: can one object be constructed from the other in a black-box manner? Result: The problem turns out highly non-trivial! In this work, we are able to construct a one-time VDF from TLP, but using the heavy hammer of indistinguishability obfuscation.