6
votes
2answers
172 views

What to consider when generating random code as part of two-factor authentication?

I want to write a patch for a two factor authentication system that someone else has started. The code is a module for a PHP content management system and sends an SMS message to a user's phone, after ...
8
votes
2answers
486 views

Is a rand from glibc's rand secure for a login key?

Same question as Is a rand from /dev/urandom secure for a login key, but with glibc's rand function instead of /dev/urandom. And what would be a sufficiently secure seed generator?
60
votes
3answers
7k views

Is a rand from /dev/urandom secure for a login key?

Lets say I want to cookie for a user, would simply going to /dev/urandom, generating a 1024 bit string, checking if it already exists (and looping till I get a unique one) suffice? Or should I be ...