QEnclave - A practical solution for secure quantum cloud computing

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 from the classical concept of a secure enclave that 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, by 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 (RSR). We show that this resource, similar to the previously introduced functionality of remote state preparation, allows blind delegated quantum computing with perfect security. Our proof under the Abstract Cryptography framework shows the construction of remote state preparation from remote state rotation while preserving security. An immediate consequence is the weakening of the requirements for blind delegated computation. While previous delegated protocols relied 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.