Jens is a Chief Scientist at Nexus, and works in many areas of cryptography including in pairing-based cryptography and Zero-knowledge Proofs (ZKPs). He was previously a Professor of Cryptology at University College, London, and as the Director of Research at DFINITY. In 2016, he published a classic paper of "On the size of pairing-based non-interactive arguments", and which defines a Zero Knowledge Proof based on pairing-based cryptography. This is now known as Groth16, and is used in many applications, including with Zcash and Tornado Cash. In 2021, he won an IACR Test of Time award for the "Simulation-sound NIZK proofs for a practical language and constant size group signature". Then, in 2023, he won the IACR Test of Time Award with Amit Sahai for the 2018 paper on "Efficient Non-Interactive Proof Systems for Bilinear Groups".

The YouTube version is here: https://www.youtube.com/watch?v=ooOYmDzoQj

Medium article: https://billatnapier.medium.com/groth16-and-proving-your-know-the-answer-to-x%C2%B2-2x-15-029f6db184d0