Latest Research

Home>Latest Research>Protecting the output of a quantum computer with random circuit samplers

Protecting the output of a quantum computer with random circuit samplers

By Zixin Huang, Pieter Kok, and Cosmo Lupo

Submitted to arXiv on 25 March 2020.

Random quantum circuit samplers have been used to demonstrate the exponential speed-up of quantum processors beyond what is tractable classically [Arute, K. et al., Nature 574, 505 (2019)]. However, useful applications for these samplers have so far been elusive. Here, we propose random circuit as efficient devices for protecting the output of a quantum computer. We consider a scenario where the server performs universal fault-tolerant quantum computation and the user gains access to the output using a pseudo-random circuit. We show that a private key much smaller than the size of the output may prevent unauthorised access. For an n-qubit computation, a standard approach requires an n-bit key to scramble the state. We provide an information-theoretic proof showing that obfuscation can be achieved with order nHmin(X) secret bits, where Hmin(X) is the min-entropy of the output of the computation. As interesting computations are expected to have large min-entropy, this represents a substantial reduction of the key size.

Read the full paper here.