One aspect of resilience on the internet is that things — notably servers and resources — move around. Sometimes moves are legitimate, such as when a popular site evolves from hosting their own website to moving to a cloud provider to using a CDN to handle the ever-increasing traffic. Sometimes the moves are not legitimate, such as when an attacker pretends to be an ecommerce or banking site and steals a user’s credentials upon login. How can the end user tell the difference between legitimate and not-so-legitimate moves? \r\n One answer to this question is Transport Layer Security, known as TLS (previously known as SSL/TLS, but nobody should be using SSL any more). Think of it as the "s" in https URLs. TLS works by having a third party, known as a certificate authority (CA), digitally sign a data blob that includes the server name and a "key" that can be used to communicate with that server.…