Named after its developers Bennett and Brassard and the year of its inception, the *BB84 protocol* is historically the first protocol for [[Quantum Key Distribution|quantum key distribution]]. In the original proposal, the [[Polarization|polarization]] of [[Photon|photons]] is used the encode quantum information. The [[No-Cloning Theorem|no-cloning theorem]] allows a [[Encryption Key|secret key]] to be exchanged using an authenticated, classical and a quantum connection. Importantly, the protocol contains a verification step to check that no eavesdropper has listened to the key exchange. Upon success, the key can be either used for a [[One-Time Pad|one-time pad]] or as key for a [[Symmetric Encryption|symmetric encryption]] scheme. >[!read]- Further Reading > - [[Quantum Network]] > - [[Quantum Repeater]] >[!ref]- References > - C. H. Bennett and G. Brassard, Quantum cryptography: Public key distribution and coin tossing, Theoretical Computer Science **560**, 7 (2014).