[function_seven]

I actually ran it through three rounds of ROT9. (http://www.rot13.com)

[Cogito]

Ahh of course, I was being silly.

3x9 === 1 mod 26, so I think you are right in saying it was encoded with ROT01.

The decoding is ROT25 == -ROT01, which is what I was thinking about. It's fun to be pedantic but it's better when you're right...