Experimental Two Way Quantum Key Distribution with Decoy State
  We report on the first demonstration of a two way Quantum Key Distribution protocol with decoy state. The experiment was conducted over free space medium and exhibits a significant increase in the maximum secure distance. 
Mohd Fared Abdul Khir, Mohd Norzaliman Mohd Zain, Iskandar Bahari,   Suryadi Soekardjo, Sahbudin Shaari
quant-ph