Tag
#QKD
3 articles
- E91: The Protocol That Turns Bell's Theorem Into an Eavesdropping Detector
Where BB84 detects eavesdroppers by watching for measurement disturbances on individual photons, E91 — proposed by Artur Ekert in 1991 — detects them by testing whether quantum correlations between entangled photon pairs violate a Bell inequality. If they do, no eavesdropper could have intervened. Here is the physics, the mathematics of the CHSH test, and why E91's entanglement-based approach leads directly to device-independent quantum cryptography.
- BB84: The Protocol That Made Eavesdropping a Physics Problem
The BB84 protocol, proposed in 1984, showed for the first time that physical law — not computational hardness — could guarantee communication security. Here is exactly how it works, why an eavesdropper cannot hide, and what the real-world limitations are.
- The Quantum Internet: How Entanglement Will Rewire Global Communication
The quantum internet is not a faster version of the internet we have. It is a parallel communication layer built on entanglement — and it will enable capabilities that classical physics makes impossible.
