On the Foundations of Quantum Key Distribution - Reply to Renner and Beyond

Abstract

In a recent note (arXiv:1209.2423) Renner claims that the criticisms of Hirota and Yuen on the security foundation of quantum key distribution arose from a logical mistake. In this paper it is shown that Renner misrepresents the claims of Yuen and also Hirota while adopting one main theorem of Yuen in lieu of his own previous error. This leads to his incoherent position which ignores quantitative security criterion levels that undermine the current security claims, a main point of the Yuen and Hirota criticisms. This security criterion issue has never been properly addressed in the literature and is here fully discussed, as are several common misconceptions on QKD security. Other foundational issues are touched upon to bring out further the present precarious state of quantum key distribution security proofs.