Security against individual attacks for realistic quantum key distribution -: art. no. 052304

I prove the security of quantum key distribution against individual attacks for realistic signals sources, including weak coherent pulses and down-conversion sources. The proof applies to the Bennett-Brassard 1984 protocol with the standard detection scheme (no strong reference pulse). I obtain a formula for the secure bit rare per time slot of an experimental setup, which can be used to optimize the performance of existing schemes for the considered scenario.