Until now, quantum cryptography has been a strictly point-to-point affair. Technology Research News announced today that a 6-node network connecting Harvard, Boston University, and BBN has been successfully deployed. Quantum cryptography uses the quantum state of photons to transmit one-time pads to a correspondent. Reading the state changes it. The benefit is that quantum-based cryptographic methods can be shown to be strongly secure without having to base those arguments on the intractability of certain mathematical problems as standard cryptography does. (read a tutorial).