In 2004, Rupert Ursin and his team at the University of Vienna teleported a photon across 600 metres under the Danube River. It was the first time quantum teleportation had been demonstrated outside a laboratory. Three years later, the same team transmitted entangled photons between two of the Canary Islands — La Palma and Tenerife — over a distance of 144 kilometres. The experiment set a world record and demonstrated that long-distance quantum communication was not merely theoretically possible. It was real.
Two decades later, Ursin has founded zerothird GmbH, a Vienna-based company that is commercialising the technology he spent a career proving. The physics has not changed. But the urgency has.
Why Encryption Is Broken — and Why Most People Do Not Know It Yet
The encryption that protects most digital communication today — the RSA and elliptic curve cryptography that secures banking systems, government networks, and internet infrastructure — is based on mathematical problems that are computationally hard. Specifically, it relies on the fact that factoring large numbers or solving certain logarithm problems takes classical computers an impractically long time.
Quantum computers change this assumption fundamentally. Shor's algorithm can factor large numbers exponentially faster on a quantum computer than on any classical machine. A sufficiently powerful quantum computer — one that does not yet exist at scale, but that multiple national programmes and private companies are actively building — could break most of today's public-key encryption infrastructure in hours rather than the millennia it would take a classical computer.
The most immediate threat is not the future quantum computer. It is an attack strategy that security researchers call "harvest now, decrypt later." Adversaries are already collecting encrypted communications and storing them. When a sufficiently powerful quantum computer arrives, that stored data becomes readable. The window to act is not when quantum computers arrive. It is now.
The zerothird Approach: Security From Physics, Not Mathematics
Classical encryption secures data by making the problem of breaking it computationally expensive. Quantum key distribution secures data by making the act of eavesdropping physically detectable. This is the distinction that Ursin has spent his career establishing in the laboratory and that zerothird is now deploying in the field.
zerothird uses entanglement-based QKD. In zerothird's approach, no key is ever transmitted. Instead, pairs of entangled photons are distributed to both endpoints. Each endpoint measures its photon independently, and the correlated results of those measurements generate identical keys at both locations — simultaneously, without any key having passed through the network. The entanglement is the key.
As Ursin has explained: "If a third party tries to eavesdrop, the system immediately sounds the alarm — because entanglement is gone." Any interception attempt destroys the entanglement and is immediately detected. The security guarantee is not computational. It is a consequence of quantum mechanics.
From the Lab to Critical Infrastructure
zerothird GmbH, founded in April 2023, is building this capability as a deployable service. The company's Key-as-a-Service model is designed for critical infrastructure operators: power grid operators, financial institutions, government agencies, and the operators of autonomous vehicle networks. Ursin brings to this commercial challenge the credibility of an academic career that includes a loophole-free Bell inequality test and recognition in the 2025 Quantum 100 list of the world's most influential quantum technology figures.
Rupert Ursin joins Human × AI on May 19, 2026, in Vienna.