Quantum cryptography: Approaching communication security from a quantum perspective

Quantum cryptography aims at solving the everlasting problem of unconditional security in private communication. Every time we send personal information over a telecom channel a sophisticate algorithm protect our privacy making our data unintelligible to unauthorized receivers. These protocols resulted from the long history of cryptography. The security of modern cryptographic systems is guaranteed by complexity: the computational power that would be needed for gaining info on the code key largely exceed available one. Security of actual crypto systems is not “by principle” but “practical”. On the contrary, quantum technology promises to make possible to realize provably secure protocols. Quantum cryptology exploits paradigmatic aspects of quantum mechanics, like superposition principle and uncertainty relations. In this contribution, after a brief historical introduction, we aim at giving a survey on the physical principles underlying the quantum approach to cryptography. Then, we analyze a possible continuous variable protocol.