QEnclave -- A practical solution for secure quantum cloud computing

TL;DR

The paper presents QEnclave, a hardware device enabling secure remote quantum computation using only classical controls, thus enhancing privacy and security in quantum cloud computing.

Contribution

Introduction of QEnclave, a practical hardware solution that secures quantum computations with classical controls, reducing client-side quantum requirements.

Findings

QEnclave can secure arbitrary quantum computations with only single-qubit rotations.

The security is modeled as Remote State Rotation, enabling perfect blind delegated quantum computing.

The protocol reduces client quantum capabilities needed for secure quantum cloud computing.

Abstract

We introduce a secure hardware device named a QEnclave that can secure the remote execution of quantum operations while only using classical controls. This device extends to quantum computing the classical concept of a secure enclave which isolates a computation from its environment to provide privacy and tamper-resistance. Remarkably, our QEnclave only performs single-qubit rotations, but can nevertheless be used to secure an arbitrary quantum computation even if the qubit source is controlled by an adversary. More precisely, attaching a QEnclave to a quantum computer, a remote client controlling the QEnclave can securely delegate its computation to the server solely using classical communication. We investigate the security of our QEnclave by modeling it as an ideal functionality named Remote State Rotation. We show that this resource, similar to previously introduced functionality of remote state preparation, allows blind delegated quantum computing with perfect security. Our proof relies on standard tools from delegated quantum computing. Working in the Abstract Cryptography framework, we show a construction of remote state preparation from remote state rotation preserving the security. An immediate consequence is the weakening of the requirements for blind delegated computation. While previous delegated protocols were relying on a client that can either generate or measure quantum states, we show that this same functionality can be achieved with a client that only transforms quantum states without generating or measuring them.