The certificate authority (CA) system does an incredible job of solving an impossible challenge. Think about it. The CAs measure control of a domain name and then issue TLS certificates that pair cryptographic keys to those names. They do this on a global scale, often automatically. It's impossible to do this perfectly, and unfortunately, they occasionally fail.

In this post I describe the challenges the CAs face, describe a history of failures, and explain the process we use to maintain confidence in the system in spite of it all.