I have a web server that authenticates and redirects from HTTP to HTTPS. Clients can then view available "downloads" in their account. I want to be able to sign these download links - as in, I want the link to only be used by the authenticated user, only once, and I want to be able to recover information about when a specific "token" was used...
What is this actually called? I can't seem to find anything about it, and I'm sure I've seen it before. I just need to find out what it's called or what a resource is regarding it so I can read about it and implement it.
As a bonus question: does anyone know offhand how to implement public key authenticated database connections in PHP (like mysql_connect(); or whatever, but when the database is on the local network instead of the same machine, and you don't want the connection sniffable)