The use of
quantum computation to perform
cryptographic functions.
While classical cryptography employs various mathematical techniques to restrict eavesdroppers from learning the contents of encrypted messages, in quantum mechanics the information is protected by the laws of physics. In classical cryptography an absolute security of information
cannot be guaranteed. The Heisenberg uncertainty principle
and quantum entanglement can be exploited in a system of secure communication, often referred to as "quantum cryptography". Quantum cryptography provides means for two parties to exchange an enciphering key over a private channel with complete security of communication.
Originally theorized by Stephen Wiesner in the late 1960s.