Quantum cryptography protocols robust against photon number splitting   attacks for weak laser pulses implementations
  We introduce a new class of quantum quantum key distribution protocols, tailored to be robust against photon number splitting (PNS) attacks. We study one of these protocols, which differs from the BB84 only in the classical sifting procedure. This protocol is provably better than BB84 against PNS attacks at zero error. 
Valerio Scarani, Antonio Acin, Gregoire Ribordy, Nicolas Gisin