How Shor's Algorithm Threatens Encryption

HN commenters point to it as a clear, approachable explanation of Shor's algorithm and what quantum computers actually do.

MinutePhysics explains Shor's algorithm, showing how a quantum computer factors large integers by finding the period of a number modulo N. It walks through the modular arithmetic and number theory that give the exponential speedup over classical factoring, and why this threatens encryption.