Relativistic Quantum Cryptography: Controlling Information by Fundamental Physics

Quantum systems carry an intrinsically quantum form of information, which
cannot be copied and allows much stronger control than classical information.
Special relativity also allows the flow of information to be controlled through
the no-superluminal-signalling principle. Together these have led to the
emerging science and technology of relativistic quantum cryptography. I
describe some applications, including verifying the location of a prisoner,
using quantum teleportation to fake anything, running a secure quantum casino,
and guaranteeing trust in the devices of untrustworthy cryptographic device builders.
I also describe the first relativistic quantum cryptographic experiment, carried out
recently by a Geneva-Singapore-Cambridge collaboration.