Fundamental And Practical Problems of QKD Security - the Actual and the   Perceived Situation
  It is widely believed that quantum key distribution (QKD) has been proved unconditionally secure for realistic models applicable to various current experimental schemes. Here we summarize briefly why this is not the case, from both the viewpoints of fundamental quantitative security and applicable models of security analysis, with some morals drawn. 
Horace P. Yuen
quant-ph