New CSRF tokens

Hey guys,

I've just committed a change to the way we generate and use CSRF tokens in rails[1]. Instead of all the stuff involving :secret and session ids, we simply take advantage of ActiveSupport::SecureRandom. This simplifies the tests and code drastically, and shouldn't have any negative impact on security.

Any feedback or reports of breakage greatly appreciated.

Also, thanks to Adam Barth and Colin Jackson of Stanford for taking the time to verify the approach with me.

[1] Change the forgery token implementation to just be a simple random st… · rails/rails@9fdb15e · GitHub

Awesome. Working fine for me so far.

Jeff