.\"	$NetBSD: rndctl.8,v 1.7 2000/08/28 13:27:37 joda Exp $
.\"
.\" Copyright (c) 1997 Michael Graff
.\" All rights reserved.
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.Dd October 12, 1997
.Dt RNDCTL 8
.Os NetBSD
.Sh NAME
.Nm rndctl
.Nd in-kernel random number generator management tool
.Sh SYNOPSIS
.Nm
.Fl CEce
.Op Fl t Ar devtype
.Op Fl d Ar devname
.Nm ""
.Fl ls
.Op Fl t Ar devtype
.Op Fl d Ar devname
.Sh DESCRIPTION
The
.Nm
program displays statistics on the current state of the 
.Xr rnd 4
pseudo-driver, and allows the administrator to control which sources
are allowed to contribute to the randomness pool maintained by 
.Xr rnd 4 ,
as well as whether a given source is counts as strongly random.
.Sh OPTIONS
The following options are available:
.Bl -tag -width 123456
.It Fl C
Disable collection of timing information for the given
device name or device type.
.It Fl c
Enable collection of timing information for the given
device name of device type.
.It Fl E
Disable entropy estimation from the collected timing information for
the given device name or device type.  If collection is still enabled,
timing information is still collected and mixed into the internal
entropy pool, but no entropy is assumed to be present.
.It Fl e
Enable entropy estimation using the collected timing information
for the given device name or device type.
.It Fl s
Display statistics on the current state of the random collection pool.
.It Fl l
List all sources, or, if the
.Fl t
or
.Fl d
flags are specified, only those specified by the
.Ar devtype
or
.Ar devname
specified.
.It Fl s
Show entropy pool statistics.
.It Fl t
All devices of type
.Ar devtype
are altered or displayed.
.It Fl d
Only the device named
.Ar devname
is altered or displayed.
.El
.Sh WARNINGS
Turning on entropy estimation from unsafe or predictable sources will
weaken system security, while turning on entropy collection from such
sources may weaken system security.
.Pp
Care should be taken when using this command.
.Sh FILES
.Bl -tag -width /dev/urandomx -compact
.It Pa /dev/random
Returns ``good'' values only
.It Pa /dev/urandom
Always returns data, degenerates to a pseudo-random generator
.El
.Sh HISTORY
The
.Nm
program was first made available in
.Nx 1.3 .
.Sh AUTHOR
The
.Nm
program was written by Michael Graff <explorer@flame.org>.
.Sh SEE ALSO
.Xr rnd 4 ,
.Xr rnd 9