Issue
I know that /dev/random blocks to wait for more entropy comes in, but why does /dev/urandom not block?
id='dv3'>
Solution
Because its purpose is not to block. That's literally what distinguishes it from /dev/random. So you don't have to worry about blocking, but the bits you get from it may not be quite as random as those from /dev/random.
According to the man page:
If there is not sufficient entropy in the entropy pool, the returned values from
/dev/urandomare theoretically vulnerable to a cryptographic attack on the algorithms used by the driver.
The man page adds:
Knowledge of how to do this is not available in the current unclassified literature, but it is theoretically possible that such an attack may exist.
Answered By - Willis Blackburn Answer Checked By - Marilyn (WPSolving Volunteer)