Secure Quantum Communcation

(c) Solvejg Skalvy

We investigate how the laws of quantum theory can boost the security of modern communication networks. By carefully designing quantum-cryptographic primitives and securely mapping them onto state-of-the-art photonic platforms, we experimentally demonstrate new applications, ranging from quantum-digital payments to quantum leader election and quantum-secured one-time programs.

In a milestone achievement, our group showed how quantum light can provide security advantages over classical methods in everyday digital payments. This combined concepts of quantum-digital signatures with quantum money to generate unforgeable cryptograms, where the customers’ sensitive information is concealed by an information-theoretically secure cryptographic function, and the commitment to the purchase is guaranteed by the laws of quantum mechanics. Thanks to the practicality of the scheme, which requires no quantum storage or stringent spacetime-constraints, a spin-off company was founded in 2024:



Publications (selected)

Demonstration of quantum-digital payments
P. Schiansky, J. Kalb, E. Sztatecsny, M.-C. Roehsner, T. Guggemos, A. Trenti, M. Bozzio, P. Walther
Nature Communications 14, 3849 (2023).

Enhancing quantum cryptography with quantum dot single-photon sources
M. Bozzio, M. Vyvlecka, M. Cosacchi, C. Nawrath, T. Seidelmann, J. C. Loredo, S. L. Portalupi, V. M. Axt, P. Michler, P. Walther
npj Quantum Information 8, 104 (2022).

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

Quantum cryptography with highly entangled photons from semiconductor quantum dots
C. Schimpf, M. Reindl, D. Huber, B. Lehner, S.F. Covre Da Silva, S. Manna, M. Vyvlecka, P. Walther, A. Rastelli,
Science Advances 7, 16 (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).