About Quantum Communication
Communication security is of strategic importance to consumers, enterprises and governments alike.
At present, it is provided by encryption via classical computers, which could be broken by a quantum computer. This motivates the development of post-quantum cryptography, i.e. encryption methods that quantum computers could not break. Secure solutions based on quantum encryption are also immune to attacks by quantum computers, and are commercially available today, as is quantum random number generation – a key primitive in most cryptographic protocols. But they can only function over distances up to 300 km: quantum information is secure because it cannot be cloned, but for the same reason it cannot be relayed through conventional repeaters. Instead, repeaters based on trusted nodes or fully quantum devices, possibly involving satellites, are needed to reach global distances. The advantage of trusted-node schemes is that they provide access for lawful intercept, as required by many nation states, and they are already being installed. The advantage of quantum repeaters, exploiting multimode quantum memories, lies in extending the distances between trusted nodes.The building blocks for fully quantum repeater schemes are twofold: a small quantum processor and a quantum interface to convert the information into photons similar to the optoelectronics devices used in today’s internet, but with quantum functionality. These building blocks have already been demonstrated in the lab, but years of R&D are still needed for them to reach the market. As soon as this happens, true internet-wide quantum-safe security could become a reality.While long-distance qubit transmission can only take place via photons, various platforms exist to realise quantum memories for storage and processing at repeater nodes. Trapped ions, atoms in optical resonators, solid-state rare earth ions, colour centres in diamond and quantum dots are the main options currently being investigated in programmes funded at both the European and the Member State level.
As well as world-leading SMEs like the Swiss firm ID Quantique, big companies like Toshiba are strongly active in this field in Europe, and national telecommunication companies, such as British Telecom, are increasingly involved, while standardisation is well under way thanks to the European Telecommunications Standards Institute (ETSI).
Source: Quantum Manifesto, May 2016