Secure Quantum Computation

We design practical protocols for the photonic implementation of secure delegated computation, including quantum homomorphic encryption and blind quantum computation primitives.

A milestone achievement of our group was the demonstration of a privacy-preserving quantum computation that combines the power of quantum computing with the security of quantum cryptography in a client-server network. By using the concept of one-way quantum computing, a blind computation could be achieved where the user’s data input, processing and output remained unknown to the quantum computer. This enabled new methods and tools that allowed us to perform the first verification of a quantum computation by using limited resources.

Publications (selected)

Experimental quantum homomorphic encryption
J. Zeuner, I. Pitsios, S.-H. Tan, A. Sharma, J. Fizsimons, R. Osellame, P. Walther,
npj Quantum Information 7, 25 (2021).

Demonstration of measurement-only blind quantum computing
C. Greganti, M.-C. Roehsner, S. Barz, T. Morimae, P. Walther
New Journal of Physics 18, 013020 (2016).

Experimental verification of quantum computation
S. Barz, J.F. Fitzsimons, E. Kashefi, P. Walther
Nature Physics 9, 727 (2013).

Demonstration of blind quantum computing
S. Barz, E. Kashefi, A. Broadbent, J. Fitzsimons, A. Zeilinger, P. Walther
Science 335, 303 (2012).