RNDCONTROL(8)

NAME
rndcontrol - a utility for manipulating the /dev/random device

SYNOPSIS
rndcontrol [-q] [-s irq_no] [-c irq_no]

DESCRIPTION
The rndcontrol command is used to set which interrupts are used to help add entropy to the CSPRNG maintained by the kernel. The /dev/random and /dev/urandom devices are the user interface to this source of randomness. Any changes take effect immediately.

The following command line options are supported:

-q  Turn off all output except errors.

-s n
    Allow IRQ n to be used as a source of randomness. This option may be repeated for more than one IRQ.

-c n
    Stop IRQ n from being used as a source of randomness. This option may be repeated for more than one IRQ.

By default, all IRQs will help develop entropy. The kernel uses a rate-limited helper thread to add the actual entropy and even fast interrupts should not detrimentally affect a running system.

FILES
/dev/random
    secure random device
/dev/urandom
    random device

SEE ALSO
srandomdev(3), random(4)

HISTORY
The rndcontrol utility first appeared in FreeBSD 2.1.5.

AUTHORS
-nosplit Theodore Ts'o wrote the core code. Mark Murray ported this code to FreeBSD and wrote the support routines and constructed the man pages.

BUGS
Sure to be some.