RANDOM(4)						   BSD Kernel Interfaces Manual 						 RANDOM(4)

NAME

     random , urandom -- random data source devices.

SYNOPSIS

     pseudo-device random

DESCRIPTION

     The random device produces uniformly distributed random byte values of potentially high quality.

     To obtain random bytes, open /dev/random for reading and read from it.

     The same random data is also available from getentropy(2).  Using the getentropy(2) system call interface will provide resiliency to file
     descriptor exhaustion, chroot, or sandboxing which can make /dev/random unavailable.  Additionally, the arc4random(3) API provides a fast
     userspace random number generator built on the random data source and is preferred over directly accessing the system's random device.

     /dev/urandom is a compatibility nod to Linux. On Linux, /dev/urandom will produce lower quality output if the entropy pool drains, while
     /dev/random will prefer to block and wait for additional entropy to be collected.	With Yarrow, this choice and distinction is not necessary,
     and the two devices behave identically. You may use either.

     The random device implements the Yarrow pseudo random number generator algorithm and maintains its entropy pool.  The kernel automatically
     seeds the algorithm with additional entropy during normal execution.

FILES

     /dev/random
     /dev/urandom

HISTORY

     A random device appeared in the Linux operating system.

Darwin								 September 6, 2001							    Darwin