  In this paper we provide an intuitive-level discussion of the challenges and
opportunities offered by quantum-based methods for supporting secure
communications, e.g., over a network. The goal is to distill down to the most
fundamental issues and concepts in order to provide a clear foundation for
assessing the potential value of quantum-based technologies relative to
classical alternatives. It is hoped that this form of exposition can provide
greater clarity of perspective than is typically offered by
mathematically-focused treatments of the topic. It is also hoped that this
clarity extends to more general applications of quantum information science
such as quantum computing and quantum sensing.
