Gone In Six Characters: Short URLs Considered Harmful for Cloud Services

freedom-to-tinker.com

[This is a guest post by Vitaly Shmatikov, professor at Cornell Tech and once upon a time my adviser at the University of Texas at Austin. — Arvind Narayanan.] TL;DR: short URLs produced by bit.ly, goo.gl, and similar services are so short that they can be scanned by brute force.