Quantum Key Distribution

Start here — plain-language overviews of what QKD is, how photons carry a secret key, and why eavesdropping is detectable in principle.

Free, hands-on ways to go deeper — a university course and a code-along notebook that simulates BB84 with and without an eavesdropper.

Where much of the underlying quantum-internet and QKD research is actually done.

QKD is provably secure in theory — these sources cover where real implementations fall short, from light-injection side channels to a national cybersecurity agency's skeptical take.

Fiber loses photons over distance — satellites and free-space optical links are how QKD is being extended to global scale.

Peer-reviewed and reference literature on QKD protocols, networking, and implementation — for readers who want the primary sources.

Where QKD stands as a real, shipping product today, and the business case for adopting it.