I read 15 Bytes from /dev/urandom, use base64 on it and cut of the last two padding characters. That's 2^120 possibilities - just guessing a valid id will requ

I read 15 Bytes from /dev/urandom, use base64 on it and cut of the last two padding characters. That's 2^120 possibilities - just guessing a valid id will require a lot of luck and a collision is very unlikely.