[sapphirecat]

> Have you thought about what happens when their IP changes?

++. When I was walking this road, I answered that question with "I'll use the user-agent instead!" Then I checked that assumption, and the Internet told me that could vary between requests as well. That was the key insight (you can't trust anything) that put me on the road to a much more standard system. (But probably still insecure, since I was younger and working for someone with NIH syndrome.)