BBM92 protocol

{{short description|Quantum protocol without Bell theorem}}

BBM92 is a quantum key distribution without Bell's theorem developed using polarized entangled photon pairs by Charles H. Bennett, Gilles Brassard and N. David Mermin in 1992.{{Cite journal |last1=Bennett |first1=Charles H. |last2=Brassard |first2=Gilles |last3=Mermin |first3=N. David |date=1992-02-03 |title=Quantum cryptography without Bell's theorem |url=https://link.aps.org/doi/10.1103/PhysRevLett.68.557 |journal=Physical Review Letters |volume=68 |issue=5 |pages=557–559 |doi=10.1103/PhysRevLett.68.557|pmid=10045931 |bibcode=1992PhRvL..68..557B |url-access=subscription }} It is named after the trio's surnames as (Bennett, Brassard and Mermin, BBM92).{{Cite web |title=INSPIRE |url=https://inspirehep.net/literature/352000%20https://ui.adsabs.harvard.edu/abs/1992PhRvL..68..557B/abstract |access-date=2022-09-19 |website=inspirehep.net}} It uses decoy state of multiple photon instead of single. The key differences in E91 protocol and B92{{Citation |last=Ekert |first=Artur K. |title=Quantum Cryptography and Bell's Theorem |date=1992 |url=https://doi.org/10.1007/978-1-4615-3386-3_34 |work=Quantum Measurements in Optics |series=NATO ASI Series |volume=282 |pages=413–418 |editor-last=Tombesi |editor-first=Paolo |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4615-3386-3_34 |isbn=978-1-4615-3386-3 |access-date=2022-09-19 |editor2-last=Walls |editor2-first=Daniel F.|url-access=subscription }} uses only two states instead of four states used by E91 protocol and BB84

{{Infobox protocol|image=File:Bbm92_work_explanations.png|developer=Charles H Bennett, Gilles Brassard and N David Mermin|caption=BBM92 protocol|introdate=February 3, 1992}}

It is used for non orthogonal quantum transmission 0 can be encrypted as 0 degree and 1 as 45 degree in diagonal basis BB92 protocol. There are no eavesdropping secure and hack proof {{Cite web |title=Department of Space demonstrates entanglement based quantum communication over 300m free space along with real time cryptographic applications - ISRO |url=https://www.isro.gov.in/update/31-jan-2022/department-of-space-demonstrates-entanglement-based-quantum-communication-over |access-date=2022-09-19 |website=www.isro.gov.in |archive-date=2022-02-01 |archive-url=https://web.archive.org/web/20220201151914/https://www.isro.gov.in/update/31-jan-2022/department-of-space-demonstrates-entanglement-based-quantum-communication-over |url-status=dead }}{{Cite web |title=BBM92 protocol |url=https://www0.gsb.columbia.edu/faculty/azeevi/PAPERS/QKD_PRA_final.pdf}}{{cite web |title=Long-distance entanglement-based quantum key distribution over optical fiber |url= https://opg.optica.org/viewmedia.cfm?uri=oe-16-23-19118&seq=0 |access-date=2024-09-05}}{{cite web|last=P. Peleso|first=Matthew |title=Daylight operation of a free space, entanglement-based quantum key distribution system |url=https://core.ac.uk/download/pdf/48631569.pdf |publisher=University of Waterloo|access-date=2024-09-05}} for distance of 200–300 m.