Research

The prime research at CrIS Lab is on cryptography, a key enabling technology for cybersecurity. In cryptography, we chiefly focus on the standard-bearer problem, called Multi-Party Computation (MPC) that allows a set of distrusting parties to jointly perform a collaborative computation on their private inputs in a way that no coalition of cheating parties can learn more information than their intended outputs. MPC finds application in any scenario that involves computation on sensitive data from two or more entities. E-election, e-auction, privacy-preserving bioinformatics, biometrics, machine-learning, outsourcing and data analytics, preventing satellites from collision are few of the many applications of MPC. We also work in the area of fault-tolerant distributed computing that includes classic problems such as broadcast and Byzantine Agreement (BA) that allow a set of distrusting parties to jointly reach agreement on their private inputs even in the face of a coalition of cheating parties. The research at CrIS Lab can be broadly classified into three areas as elaborated below:

Foundations of MPC

The foundational questions for MPC and its building blocks such as circuit garbling, oblivious transfer (OT), commitment schemes, zero-knowledge protocols, verifiable secret sharing (VSS), public key encryptions (PKE), are concerned with the feasibility of realizing these tasks, finding inherent lower bounds on the resources needed for solving these tasks and finding resource-efficient constructions. The resource required by a cryptographic protocol is determined by its computation, round and communication complexity.

Fault-tolerant Distributed Computing

This area includes classic problems such as Byzantine Agreement and message communication over untrusted network and involves foundational feasibility, efficiency and optimality questions as in the MPC domain.

Applied MPC

Building practically efficient constructions for MPC and its building blocks is the primary concern here.

Publications / Preprints

2019

BLAZE: Blazing Fast Privacy-Preserving Machine Learning

Authors: Arpita Patra, Ajith Suresh

Under Submission

On the Exact Round Complexity of Best-of-both-Worlds Multi-party Computation

Authors: Arpita Patra, Divya Ravi, Swati Singla

Under Submission

FLASH: Fast and Robust Framework for Privacy-preserving Machine Learning

Authors: Megha Byali, Harsh Chaudhari, Arpita Patra, Ajith Suresh

Under Submission

Trident: Efficient 4PC Framework for Privacy Preserving Machine Learning

Authors: Harsh Chaudhari, Sai Rahul Rachuri, Ajith Suresh

Under Submission

Beyond Honest Majority: The Round Complexity of Fair and Robust Multi-party Computation [Link]

Authors: Arpita Patra, Divya Ravi

ASIACRYPT 2019

ASTRA: High Throughput 3PC over Rings with Application to Secure Prediction [Link]

Authors: Harsh Chaudhari, Ashish Choudhury, Arpita Patra, Ajith Suresh

ACM CCSW 2019, PPML 2019

Fast Actively-Secure 5-Party Computation with Security Beyond Abort [Link]

Authors: Megha Byali, Carmit Hazay, Arpita Patra, Swati Singla

CCS 2019

2018

Optimal Extension Protocols for Byzantine Broadcast and Agreement [Link]

Full and extended version of PODC'16 and OPODIS'11

Authors: Chaya Ganesh, Arpita Patra

Under Submission

Fast Secure Computation for Small Population over the Internet [Link]

Authors: Megha Byali, Arun Joseph, Arpita Patra, Divya Ravi

CCS 2018

On the Exact Round complexity of Secure Three-party Computation [Link]

Authors: Arpita Patra, Divya Ravi

CRYPTO 2018

Almost-Surely Terminating Asynchronous Byzantine Agreement Revisited [Link]

Authors: Laasya Bangalore, Ashish Choudhury, Arpita Patra

PODC 2018

On the power of Hybrid Networks in Multi-party Computation [Link]

Authors: Arpita Patra, Divya Ravi

IEEE Transactions on Information Theory

Crash-Tolerant Consensus in Directed Graph Revisited [Link]

Authors: Ashish Choudhury, Gayathri Garimella, Arpita Patra, Divya Ravi, Pratik Sarkar

DISC 2017 (Brief Announcement); SIROCCO 2018 (Full Paper)

Efficient Adaptively Secure Zero-knowledge from Garbled Circuits [Link]

Authors: Chaya Ganesh, Yashvanth Kondi, Arpita Patra, Pratik Sarkar

PKC 2018

2017

An Efficient Framework for Unconditionally-secure Multiparty Computation [Link]

Authors: Ashish Choudhary, Arpita Patra

IEEE Transactions on Information Theory

Round and Communication Efficient Unconditionally-secure MPC with t < n/3 in Partially Synchronous Network. [Link]

Authors: Ashish Choudhury, Arpita Patra, Divya Ravi

International Conference on Information Theoretic Security (ICITS) 2017

Privacy-Free Garbled Circuits for Formulas: Size Zero and Information-Theoretic [Link]

Authors: Yashvanth Kondi, Arpita Patra

CRYPTO 2017

Fast Actively Secure OT Extension for Short Secrets [Link]

Authors: Arpita Patra, Pratik Sarkar, Ajith Suresh

NDSS 2017

2016

Efficient One-Sided Adaptively Secure Computation [Link]

Authors: Carmit Hazay, Arpita Patra

Journal of Cryptology 2016, TCC 2014

Broadcast Extensions with Optimal Communication and Round Complexity [Link]

Authors: Chaya Ganesh, Arpita Patra

PODC 2016

Linear Overhead Robust MPC with Honest Majority Using Preprocessing [Link]

Authors: Ashish Choudhury, Emmanuela Orsini, Arpita Patra, Nigel Smart

SCN 2016

2015

Efficient Asynchronous Verifiable Secret Sharing and Multiparty Computation [Link]

Authors: Ashish Choudhary, Arpita Patra, C. Pandu Rangan

Journal of Cryptology 2015

Selective Opening Security for Receivers [Link]

Authors: Carmit Hazay, Arpita Patra, Bogdan Warinschi

ASIACRYPT 2015

Adaptively Secure Computation with Partial Erasures [Link]

Authors: Carmit Hazay, Yehuda Lindell, Arpita Patra

PODC 2015

Optimally Resilient Asynchronous MPC with Linear Communication Complexity [Link]

Authors: Ashish Choudhury, Arpita Patra

ICDCN 2015

2014

Efficient Asynchronous Byzantine Agreement with Optimal Resilience [Link]

Authors: Ashish Choudhary, Arpita Patra, C. Pandu Rangan

Distributed Computing Journal, volume 27, number 2, pp. 111- 146, 2014

Anonymous Authentication with Shared Secrets [Link]

Authors: Joel Alwen, Martin Hirt, Ueli Maurer, Arpita Patra, Pavel Raykov

LatinCrypt 2014

Key-Indistinguishable Message Authentication Codes [Link]

Authors: Joel Alwen, Martin Hirt, Ueli Maurer, Arpita Patra, Pavel Raykov

SCN 2014

Reducing the Overhead of MPC over a Large Population [Link]

Authors: Ashish Choudhury, Arpita Patra, Nigel P. Smart

SCN 2014

One-Sided Adaptively Secure Two-Party Computation [Link]

Authors: Carmit Hazay, Arpita Patra

TCC 2014, LNCS 8349, pp. 368-393, 2014

Thesis 2017

Fast Actively Secure OT Extension for Short Secrets [PDF]

Masters' Thesis by Ajith S

On the Authenticity of Garbling Schemes [PDF]

Masters' Thesis by Yashvanth Mohan Kondi

2016

On Secure Computation in Hybrid Network [PDF]

Masters' Thesis by Divya Ravi

On Scalable Secure Computation [PDF]

Masters' Thesis by Dheeraj Ram

2015

On Verifiable Secret Sharing With Honest Majority [PDF]

Masters' Thesis by Aakar Deora

Posters
  • Fast Actively Secure Five Party Computation with Security Beyond Abort
  • High Throughput Asymmetric 3PC: A Secure Prediction Framework
  • On the Exact Round Complexity of Best-of-both-Worlds MPC
  • Computing on Private Data in High Latency Networks
  • Turing Award Winners in Cryptography
  • Secure MPC, Arpita Patra
  • Blazing Fast Actively Secure OT Extension Protocol
  • Δ-EIG Protocol for Byzantine Agreement
  • Distributed Consensus in Byzantine Failure Model