random(4) – Linux manual page

http://www.kernel.org/doc/man-pages/online/pages/man4/random.4.html

The character special files /dev/random and /dev/urandom (present since Linux 1.3.30) provide an interface to the kernel’s random number generator. File /dev/random has major device number 1 and minor device number 8. File /dev/urandom has major device number 1 and minor device number 9.

urandom(4): kernel random number source devices – Linux man page

http://linux.die.net/man/4/urandom

The character special files /dev/random and /dev/urandom (present since Linux 1.3.30) provide an interface to the kernel’s random number generator. File /dev/random has major device number 1 and minor device number 8. File /dev/urandom has major device number 1 and minor device number 9.

WebCite query result

http://www.webcitation.org/5gOzGLECz

The pseudo-device /dev/random exists due to a collision between modern networks, and the historical design of the Unix operating system. First, we assume that the users of a system need cryptography, either in a form they use directly (ie, PGP), or that the system uses on their behalf (SSL and IPSec). All such cryptography requires the generation of a large amount of random or pseudo-random bits. There are other uses for such random bits, but these are few and far between, and /dev/random was initially designed for crypto, which is why it tries so hard to be cryptographically secure.