Nikhil Vanjani

PhD Student

Carnegie Mellon University

About

Update: I am applying to postdoctoral positions and industry research positions this upcoming cycle. Feel free to check out my CV and send me an email.

I am a final-year PhD student at Carnegie Mellon University, where I am fortunate to have Elaine Shi as my advsior. I am interested in cryptography and blockchains, and I aim to design expressive, efficient, and privacy-preserving systems that bridge the gap between provable security and real-world deployment.

My work so far has focused on developing new techniques for functional encryption (FE) and exploring its applications to decentralized systems. While general-purpose FE remains inefficient, my work bridges theory and practice by (i) uncovering new applications of FE, (ii) advancing security and efficiency of FE for restricted function classes, and (iii) replacing FE with lighter primitives to meet real-world performance goals.

Previously, I received MS in Information Security in 2021 from Carnegie Mellon University where I was also advised by Elaine. Even before, I received B.Tech. in Computer Science and Engineering in 2018 from IIT Kanpur. I have done research internships in industry at NTT Research, 0xPARC Foundation, and Algorand. Even before, I worked on distributed systems as a software developer at Cohesity.

Recent News

October 2025: Gave a talk at the Stanford Security Seminar
October 2025: Gave a talk at the NTT Research CIS Seminar
September 2025: Gave a talk at the CMU Crypto Seminar
September 2025: Our work on broadening functionality and improving efficiency of Functional Adaptor Signatures got accepted to S&P (Oakland)‘26
August 2025: Our work on showing fully adaptive security of the classic Lewko-Waters MA-ABE got accepted to Asiacrypt'25
June 2025: Attended Cryptography 10 Years Later program at Simons Institute
June 2025: Research Internship at NTT Research
March 2025: Research Internship at 0xPARC Foundation
August 2024: Our work on enabling functional fair exchange via Functional Adaptor Signatures got accepted to CCS'24
June 2024: Research Internship at NTT Research

Publications

*: denotes first author

Large-Universe (Multi-Authority) ABE from LWE.
Pratish Datta, Yannis Rouselakis, Junichi Tomida, Nikhil Vanjani.
In Submission, 2025.

Unbounded Large-Universe Decentralized MA-ABE from Static Assumptions.
Pratish Datta, Junichi Tomida, Nikhil Vanjani.
In Submission, 2025.

New Constructions of Functional Adaptor Signatures : Broader Functions and Improved Efficiency.
Nikhil Vanjani*, Garrett Greiner*, Sri Aravinda Krishnan Thyagarajan, Pratik Soni.
(To Appear) In IEEE Symposium on Security and Privacy, 2026.

Fully Adaptive Decentralized MA-ABE: Simplified, Optimized, ASP Supported.
Pratish Datta, Junichi Tomida, Nikhil Vanjani.
(To Appear) In Asiacrypt, 2025.

Functional Adaptor Signatures: Beyond All-or-Nothing Blockchain-based Payments.
Nikhil Vanjani*, Pratik Soni, Sri Aravinda Krishnan Thyagarajan.
In ACM SIGSAC Conference on Computer and Communications Security (CCS), 2024.
Contributed talk at Theory and Practice of Multi-Party Computation (TPMPC) Workshop, 2025.

Non-Interactive Anonymous Router with Quasi-Linear Router Computation.
Rex Fernando, Elaine Shi, Pratik Soni, Nikhil Vanjani, Brent Waters.
In Theory of Cryptography Conference (TCC), 2023.

Multi-Client Inner Product Encryption: Function-Hiding Instantiations Without Random Oracles.
Elaine Shi, Nikhil Vanjani (randomized author order).
In International Conference on Practice and Theory of Public-Key Cryptography (PKC), 2023.

Multi-Input Inner Product Encryption: Function-Hiding Instantiations without Random Oracles.
Nikhil Vanjani.
Masters thesis.

Talks

Fully Adaptive Decentralized MA-ABE: Simplified, Optimized, ASP Supported.
Stanford Security Seminar: October 2025
NTT Research CIS Seminar: October 2025
CMU Crypto Seminar: September 2025

Fair Exchange on Blockchains.
Invited Lecture at University of Utah: October 2024

Functional Adaptor Signatures: Beyond All-or-Nothing Blockchain-based Payments.
ACM CCS: October 2024

Non-Interactive Anonymous Router with Quasi-Linear Router Computation.
IACR TCC: December 2023
Ph.D. Qualifying Exam, CMU : November 2022

Multi-Client Inner Product Encryption: Function-Hiding Instantiations Without Random Oracles.
IACR PKC: May 2023
CMU Theory Lunch: April 2023

Multi-Input Inner Product Encryption: Function-Hiding Instantiations without Random Oracles.
Masters thesis defense, CMU : November 2021

Attribute-based Signatures for Unbounded Circuits in the Random Oracle Model.
Cryptography Reading Group, IITM : July 2020

Obfuscation of Probabilistic Circuits and Applications.
Course Project for Computing on Encrypted Data, IITM : November 2019

Two case studies on advances in Blockchains: Algorand, Zcash.
Seminar Talk for National Blockchain Project, IITK : April 2018

Fully Homomorphic Encryption.
Course Project for Linear Algebra Tools for Theoretical CS, IITK : April 2018

On Lattices, Learning With Errors, Random Linear Codes, and Cryptography.
Course Project for Quantum Computing, IITK : October 2017

Research Experience

Research Intern

NTT Research

Jun 2025 – Aug 2025 Sunnyvale

Pioneered new attribute-based encryption schemes that expanded functionality and significantly improved efficiency, advancing the practicality of lattice-based cryptography

Research Intern

0xPARC Foundation

Mar 2025 – May 2025 Pittsburgh

Benchmarked modern zero-knowledge proof systems (Plonky2/Plonky3), providing performance insights to guide practical adoption of advanced cryptographic protocols

Research Intern

NTT Research

Jun 2024 – Aug 2024 Sunnyvale

Developed foundational advances in multi-authority attribute-based encryption by proving full adaptive security for the classic Lewko–Waters scheme and designing the first scheme for Arithmetic Span Programs

Intern - Smart Contracts Researcher

Theory Group, Algorand

May 2021 – Aug 2021 Pittsburgh

Investigated cryptographic tools needed to enable building complex and powerful Layer 2 Smart Contracts in AlgoClarity (Algorand’s version of the Clarity Smart Contract Language).

Research Assistant

Cryptography Group, IIT Madras

Aug 2019 – Jun 2020 Chennai

Designed a blockchain-based voting system with support for vote verification to enable voters to vote from anywhere with the goal of increasing voter turnout.