Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (NetBSD-2.0)
Apropos / Subsearch:
optional field

ARC4RANDOM(9)            BSD Kernel Developer's Manual           ARC4RANDOM(9)

     arc4random -- arc4 random number generator

     #include <&lt;sys/types.h>&gt;
     #include <&lt;sys/systm.h>&gt;


     The arc4random() function provides a high quality 32-bit pseudo-random
     number very quickly.  arc4random() seeds itself on a regular basis from
     the kernel strong random number subsystem described in rnd(4).  On each
     call, an ARC4 generator is used to generate a new result.  The
     arc4random() function uses the ARC4 cipher key stream generator, which
     uses 8*8 8 bit S-Boxes.  The S-Boxes can be in about (2**1700) states.

     arc4random() fits into a middle ground not covered by other subsystems
     such as the strong, slow, and resource expensive random devices described
     in rnd(4) versus the fast but poor quality interfaces such as random().

     arc4random(3), rnd(4)

     An algorithm called RC4 was designed by RSA Data Security, Inc.  It was
     considered a trade secret, but not trademarked.  Because it was a trade
     secret, it obviously could not be patented.  A clone of this was posted
     anonymously to USENET and confirmed to be equivalent by several sources
     who had access to the original cipher.  Because of the trade secret situ-
     ation, RSA Data Security, Inc. can do nothing about the release of the
     ARC4 algorithm.  Since RC4 used to be a trade secret, the cipher is now
     referred to as ARC4.

     These functions first appeared in OpenBSD 2.1.

BSD                             April 15, 1997                             BSD