The Key Distribution Problem
Explain why secure key exchange was impossible before Diffie-Hellman.
Welcome
For centuries, secure communication required a prior secure channel to exchange keys. In this lesson we understand this ancient problem and why it stumped cryptographers until 1976.
The Ancient Dilemma
If Alice and Bob want to communicate securely, they need a shared key. But to exchange that key securely, they already need a secure channel. It's circular — seemingly unsolvable.
All lessons in this course
- The Key Distribution Problem
- Diffie-Hellman Key Exchange Math
- ECDH: Elliptic Curves for Key Exchange
- Forward Secrecy & Ephemeral Key Exchange