Swisscom and German start-up test Quantum security solution

For some time now, security experts have been concerned about how secure existing encryption methods are in the dawning age of quantum computing. Swisscom, Switzerland's largest telecommunications provider, has now successfully tested a new quantum-secure method for key transmission using entangled light particles in a real network in collaboration with the German start-up company Quantum Optics Jena (QOJ).

Thanks to quantum computing, complex calculations can be carried out in a very short time. And this brings with it the risk that previous encryption methods will become vulnerable. Symmetric encryption methods, in which the sender and receiver use the same key to encrypt and decrypt data, are considered to be fairly secure, even against quantum computers. However, this key must be exchanged between the sender and receiver in a secure way before the actual communication takes place and must be kept secret by both parties.

In order to guarantee the security of data transmission in the future, a new generation of quantum-safe procedures has been and is being developed as part of so-called post-quantum security. Two approaches are being pursued: Post Quantum Cryptography (PQC) uses encryption algorithms that are difficult to solve even for quantum computers. This means that data remains secure even if a system is massively attacked. Quantum Key Distribution (QKD), on the other hand, relies on quantum physical properties to transfer keys. These are based on the principle that every observation of a quantum object changes it.

Proof of concept

In collaboration with Quantum Optics Jena, Swisscom has carried out a test for quantum key exchange (QKD) in Swisscom's existing fiber optic network as a proof of concept. This involved generating entangled photon pairs (photons are particles of light, i.e. quantum objects). In quantum physics, we speak of entanglement when particles, such as photons in this case, are connected to each other in such a way that a change in the state of one particle directly affects the state of the other, regardless of how far apart they are. This entanglement is used for the secure transmission of the key.

The specific properties of the photon are known to both parties transmitting the key. If a third party attempts to intercept the key during transmission or create a copy of the photon, the sender and receiver will know that the key transmission has been compromised. Communication can then be interrupted immediately to protect the data.

Since even supercomputing power cannot bend the laws of physics, quantum cryptography is therefore protected by the laws of nature itself. During the entire test period, entangled photon pairs, i.e. quantum-safe keys, were reliably exchanged between sender and receiver via the Swisscom fiber optic network, Swisscom reports. With this test, the telco and Quantum Optics Jena aimed to demonstrate the applicability of one of the first commercially available entanglement-based QKD solutions in a real telecommunications network. The successful test is a good basis for further evaluating Post Quantum Security solutions and demonstrates the potential for possible network integration, writes Swisscom.

(dahe)