Once, many years ago, I secured my website. I'm struggling to remember exactly what I did. I believe I generated a certificate (or a token???) that I delivered to a select few people I wanted to grant access to. My site somehow checked to see if the request included this certificate/token/whatever and only allowed the request through if it had one, failing fast if it wasn't valid.
Memory has failed me, so I'm not sure of the terminology. Can someone provide terminology (and/or a link) to what I'm trying to accomplish?
