Quantum key distribution with time coding and decoy states

Modern information security systems require use of cryptographic key distribution systems connecting two remote parties. In the present work we propose modified quantum key distribution protocol with time coding and present analysis of practically feasible attacks on this protocol as well as some experimental results, that show the possibility of its successful implementation.Our analysis of security of the proposed protocol includes short-pulse attack, where Eve´s pulse has duration 50 ns, and long-pulse attack (Eve´s pulse duration is 100 ns). Our protocol proved to be secure for both of them. We have made preliminary experiments, where the above described protocol has been implemented in fibre optic QKD line with 850 nm photons. Quantum bit error rate obtained is below 1% for 5 km fibre optic line.