Physicists Develop Quantum Version of Public Key Encryption

The fundamental problem of private communication is ensuring its security.

That's always been a tricky task but in recent years, cryptographers have added a powerful new weapon to their armoury: quantum key distribution. With this tool, it is possible to use the bizarre properties of the quantum world to send a message in such a way that guarantees its security. The security of this system is a fact of nature. In the language of cryptography, quantum key distribution it is information-theoretically secure.

Although this sounds perfect, it does have some drawbacks. One of them is that while it is useful for one to one communication, it's not so good for universal communication over a network. That's because everybody on the network has to swap a secret key with everybody else to ensure they can chat securely. And that introduces a significant communications overhead.