Quantum Key Leasing for PKE and FHE with a Classical Lessor
, University of Texas
Date: Friday, November 17, 2023
Time: 10:30 AM to 12:00 PM Note: all times are in the Eastern Time Zone
Location: G-882, Hewlett Room
Event Type: Seminar
Speaker URL: None
TALK: Quantum Key Leasing for PKE and FHE with a Classical Lessor
In this work, we consider the problem of secure key leasing, also known as revocable cryptography (Agarwal et. al. Eurocrypt' 23, Ananth et. al. TCC' 23), as a strengthened security notion of its predecessor put forward in Ananth et. al. Eurocrypt' 21. This problem aims to leverage unclonable nature of quantum information to allow a lessor to lease a quantum key with reusability for evaluating a classical functionality. Later, the lessor can request the lessee to provably delete the key and then the lessee will be completely deprived of the capability to evaluate.
In this work, we construct a secure key leasing scheme to lease a decryption key of a (classical) public-key, homomorphic encryption scheme from standard lattice assumptions. We achieve strong form of security where:
* The entire protocol uses only classical communication between a classical leaser (client) and a quantum lessee (server).
* Assuming standard assumptions, our security definition ensures that every computationally bounded quantum adversary could not simultaneously provide a valid classical deletion certificate and yet distinguish ciphertexts.
Our security relies on the hardness of learning with errors assumption. Our scheme is the first scheme to be based on a standard assumption and satisfying the two properties above.
Joint work with Orestis Chardouvelis, Vipul Goyal, Aayush Jain
Created by Felicia Raton at Thursday, November 09, 2023 at 7:56 AM.