When developing WCF services that interact with a custom Security Token Service (STS), you will need to create at least one X.509 certificate. If you have access to a trusted certificate authority – e.g. a Windows Active Directory domain – then this task is pretty simple. But if you don’t, or maybe you would just rather create a set of self-signed certificates, here is an approach that works well for me. This particular scenario utilizes three separate certificates. The first one is named “localhost”...