Talk:Unix directory structure

urandom and random

Are Unix and Linux different in this case? My man page says the following:

 When  read,  the  /dev/random  device  will only return random bytes 
 within the estimated number of bits of   noise in the entropy pool.  /dev/random
 should be suitable for uses that need very high quality randomness such as one-time 
 pad or key generation.  When the entropy pool is  empty,  reads
 from /dev/random will block until additional environmental noise is gathered.

 A  read from the /dev/urandom device will not block waiting for more entropy.
 As a result, if there is not sufficient entropy in the entropy pool,
 the returned values are theoretically vulnerable to a cryptographic 
 attack on the algorithms used by the driver.  Knowledge of how to  do  this  is
 not  available  in  the current non-classified literature, but it is 
 theoretically possible that such an attack may exist.  If this is a concern in
 your application, use /dev/random instead.

--Alexander Wiebel 10:30, 7 February 2008 (CST)