When creating an email or server certificate, there is one important final step: The Subject Alternative Name (SAN). This is the attribute that people most often ignore, that is commonly missing completely in certificates or used incorrectly which causes all kind of undesired behaviour – putting the security of servers…

Before we can delve into the wonderful world of certificates, we first need to understand some basic cryptographic terms and operations, but don't worry, it will be far less technical than you might fear and there will be barely any math involved. Let's get started!