Secure quantum cloud computing and quantum-secure classical computers

Schematic illustration of the general idea of quantum cloud computing

High precision automated polarization control system

Super-conductive nano-wire detectors in their cryostat


One of our group’s research focuses is the protection of data and software for quantum and classical computers in computer networks. For this framework of delegated quantum computation, quantum clouds and quantum web photonic systems are ideally suited by allowing for communicating and computing quantum information.

A milestone achievement of our group was the first 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. Our research is also dedicated to achieving a hitherto unknown level of software and data protection for classical computing.


Publications (selected):

Probabilistic one-time programs using quantum entanglement
M.-C. Röhsner, J. A. Kettlewell, J. Fitzsimons, P. Walther,
npj Quantum Information 7, 98 (2021).

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).

Quantum advantage for probabilistic one-time programs
M.-C. Roehsner, J. A. Kettlewell, T. B. Batalhão, J. F. Fitzsimons, P. Walther
Nature Communications 9, 5225 (2018).

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).


Further publications...