A quantum bit commitment scheme provably unbreakable by both parties

We describe a complete protocol for bit commitment based on the transmission of polarized photons. We show that under the laws of quantum physics, this protocol cannot be cheated by either party except with exponentially small probability (exponential in the running time needed to implement the honest protocol). A more thorough analysis is required to adjust all the constants used in this paper to get the best performance from our construction. Better performances may probably be achieved by using a third conjugate transmission-reception basis of circular polarization