Q

Quantum Cryptography

Quantum cryptography is a young field of cryptography, that exploits quantum-mechanical effects. For example: single photons with certain polarization are used for secure data-transmission. Even eavesdropping can be proved, because if somebody listened to the transmitted data, he made measurements and these measurements polluted the physical data. But the commercial implementation is not yet possible, because in scientific field experiments only short transmission ranges (less than 20 km) could be achieved.