Simple explanation on why QKD keys have not been proved secure

TL;DR

The paper challenges the common interpretation of the trace distance criterion in quantum key distribution, providing a counter-example and discussing its implications for security proofs.

Contribution

It presents a simple counter-example that questions the prevalent interpretation of trace distance as failure probability in QKD security.

Findings

Counter-example undermines the trace distance interpretation

Implications for security proofs in QKD protocols

Highlights need for revised security criteria

Abstract

A simple counter-example is given on the prevalent interpretation of the trace distance criterion as failure probability in quantum key distribution protocols. A summary of its ramifications is listed.