OAuth and OpenID Connect basics
Basic authentication is simple to implement, and if you need to work with legacy systems, there's a good chance you will run into it. It's not recommended to start new projects using basic authentication though.
There is no shortage of acronyms for protocols in the identity space, and .NET Framework has relied upon different authentication and authorization protocols over the years. We are not able to delve into all of them, nor to do a comparison of the strengths and weaknesses of them.
The most popular set of protocols used for AuthN and AuthZ purposes these days is OAuth and OpenID Connect (OIDC), so we will look at parts of both the theory and practical implementations. OAuth is the base protocol and OIDC builds on top of this, so there are some overlapping details we will get back to.
Looking back at basic authentication, we already mentioned that a drawback is the fact that the passwords are transferred over the wire. Both the...