BB84 protocol

BB84 is the first quantum key distribution protocol. It was developed by Charles Bennet and Gilles Brassard in 1984 based on Heisenberg’s principle. The security of BB84 comes from the no-cloning theorem and the ability to detect eavesdropping. BB84 QKD systems transmit individual photons, polarizing filters on the sender’s side set each photon’s orientation, while the receiver uses beam splitters to read it. By comparing photon orientations, the sender and receiver can obtain the cryptographic key.

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Related QSNP publications

Security of hybrid BB84 with heterodyne detection. Jasminder S Sidhu, Rocco Maggi, Saverio Pascazio and Cosmo Lupo.

Jasminder S Sidhu et al 2025 Quantum Sci. Technol. 10 025012