International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Rate-1 Quantum Fully Homomorphic Encryption

Orestis Chardouvelis
Nico Döttling
Giulio Malavolta
DOI: 10.1007/978-3-030-90459-3_6
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Abstract: Secure function evaluation (SFE) allows Alice to publish an encrypted version of her input m such that Bob (holding a circuit C) can send a single message that reveals C(m) to Alice, and nothing more. Security is required to hold against malicious parties, that may behave arbitrarily. In this work we study the notion of SFE in the quantum setting, where Alice outputs an encrypted quantum state |\psi> and learns C(|\psi>) after receiving Bob's message. We show that, assuming the quantum hardness of the learning with errors problem (LWE), there exists an SFE protocol for quantum computation with communication complexity (||\psi>|+|C(|\psi>)|)(1+o(1)), which is nearly optimal. This result is obtained by two main technical steps, which might be of independent interest. Specifically, we show (i) a construction of a rate-1 quantum fully-homomorphic encryption and (ii) a generic transformation to achieve malicious circuit privacy in the quantum setting.
Video from TCC 2021
  title={Rate-1 Quantum Fully Homomorphic Encryption},
  booktitle={Theory of Cryptography;19th International Conference},
  author={Orestis Chardouvelis and Nico Döttling and Giulio Malavolta},