  The current maturity of the quantum-secured optical data channels based on
the Quantum Key Distribution (QKD) technology is at the deployment level in
metro environments, while R&D efforts are also being conducted towards
long-distance deployments. A great deal of research has been conducted on the
achievable Secure Key Rate (SKR) for quantum channels. However, one of the
major questions for network operators is the required SKR for the deployment of
quantum-secured channels. This article addresses this question by defining the
required SKR for quantum-secured optical channels and provides guidelines
towards optimizing this parameter. \copyright 2023 The Author(s)
