The classic stable-matching algorithm of Gale and Shapley and subsequent variants by, Roth and Abdulkadiroglu et al. have been used successfully in a number of real-world scenarios, including the assignment of medical-school graduates to residency programs, New York City teenagers to high schools, and Norwegian and Singaporean students to schools and universities. One shortcoming of...Read More

Discussions about encryption policy in India often occur within ideological bubbles, or are simply critical without offering constructive solutions. How can we build encryption policy that defends our constitutional rights in word and in spirit while also enabling law enforcement and others to operate reasonably in the digital world. Blaming tech companies for reduced privacy...Read More

Current security and authentication systems are computer-centric: something like a password is easy to implement on a computer, so we end up using it for security even though we know that humans are really bad at keeping track of them. Is there are better, human-centric way of managing security and authentication — where humans perform...Read More

Authors: Prashant Agrawal, Subodh Sharma, Subhashis Banerjee.
Venue: The India Forum, August, 2021
Link: https://www.theindiaforum.in/article/blockchain-vs-public-bulletin-board-integrity-elections-and-electoral-rollsRead More

Authors: Prashant Agrawal, Kabir Tomer, Subodh Sharma, Subhashis Banerjee.
Venue: Working paper, 2021Read More

Overcoming the threat of coercion attacks (where a legitimate user is forced to give up their credentials) in a cryptographic system has been a top priority for system designers since the birth of cyber-security. One way to overcome such a threat is to leverage implicit memory to construct a defense against so-called rubber-hose attacks where...Read More

India’s Aadhaar is the largest biometric identity system in history, designed to help deliver subsidies, benefits, and services to India’s 1.36 billion residents. The Unique Identification Authority of India (UIDAI) is responsible for providing each resident (not each citizen) with a distinct identity—a 12-digit Aadhaar number—using their biometric and demographic details. We produce the first...Read More

A verifiable delay function (VDF) is a function that takes a pre-determined time to compute, even on parallel processors, and once computed, its output can be quickly verified by anyone. We are working on a number of novel constructions of VDFs, uVDFs (Unique VDFs), and cVDFs (Continuous VDFs) from point multiplication on elliptic curves, along...Read More

One of the major drawbacks to using garbled circuits for two-party secure computation (where two parties can jointly compute an agreed-upon function of their inputs while keeping said inputs secret) is that they can only be used once and need to be regenerated, essentially from scratch, for subsequent computations. While we know that “refreshing” a...Read More

A delay function is a cryptographic technique used for adding delay into the function computation. A verifiable delay function or VDF (Boneh et al., CRYPTO ’18) is a publicly-verifiable function that takes a predetermined amount of to compute, regardless of parallelization. The downside of standard VDFs is that intermediate steps of the computation are not...Read More