Cryptography with Certified Deletion *Presented Virtually

Dakshita Khurana (University of Illinois Urbana-Champaign) https://simons.berkeley.edu/talks/dakshita-khurana-university-illinois-urbana-champaign-2023-05-05 Minimal Complexity Assumptions for Cryptography Quantum information unlocks access to new cryptographic capabilities that are impossible to realize with classical information alone. This talk will focus on the task of certified deletion of encrypted secrets. This enables a party holding an encoding of a secret to certify that the secret has been information-theoretically deleted, and cannot be recovered in the future, even if the underlying key is leaked, or mathematical problems from which the encryption scheme derives security become easy to solve. I will give an overview of methods to compile vanilla cryptosystems including public-key encryption, attribute-based encryption, witness encryption, fully homomorphic encryption, obfuscation, and functional encryption into their counterparts allowing certified deletion. I will also describe some recent progress towards ensuring that certificates of deletion can be publicly verified, based on weak cryptographic assumptions. This talk is based on a sequence of works, the first joint with James Bartusek, the second with James Bartusek, Sanjam Garg, Vipul Goyal, Giulio Malavolta, Justin Raizes and Bhaskar Roberts, the third with James Bartusek and Alexander Poremba, and the fourth with James Bartusek, Giulio Malavolta, Alexander Poremba and Michael Walter.