1.\" $NetBSD: rndctl.8,v 1.12 2002/02/08 01:30:46 ross Exp $ 2.\" 3.\" Copyright (c) 1997 Michael Graff 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. The name of the author may not be used to endorse or promote products 15.\" derived from this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 22.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 24.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.Dd October 12, 1997 30.Dt RNDCTL 8 31.Os 32.Sh NAME 33.Nm rndctl 34.Nd in-kernel random number generator management tool 35.Sh SYNOPSIS 36.Nm 37.Fl CEce 38.Op Fl t Ar devtype 39.Op Fl d Ar devname 40.Nm "" 41.Fl ls 42.Op Fl t Ar devtype 43.Op Fl d Ar devname 44.Sh DESCRIPTION 45The 46.Nm 47program displays statistics on the current state of the 48.Xr rnd 4 49pseudo-driver, and allows the administrator to control which sources 50are allowed to contribute to the randomness pool maintained by 51.Xr rnd 4 , 52as well as whether a given source is counts as strongly random. 53.Pp 54The following options are available: 55.Bl -tag -width 123456 56.It Fl C 57Disable collection of timing information for the given 58device name or device type. 59.It Fl c 60Enable collection of timing information for the given 61device name of device type. 62.It Fl E 63Disable entropy estimation from the collected timing information for 64the given device name or device type. If collection is still enabled, 65timing information is still collected and mixed into the internal 66entropy pool, but no entropy is assumed to be present. 67.It Fl e 68Enable entropy estimation using the collected timing information 69for the given device name or device type. 70.It Fl s 71Display statistics on the current state of the random collection pool. 72.It Fl l 73List all sources, or, if the 74.Fl t 75or 76.Fl d 77flags are specified, only those specified by the 78.Ar devtype 79or 80.Ar devname 81specified. 82.It Fl t 83All devices of type 84.Ar devtype 85are altered or displayed. 86.It Fl d 87Only the device named 88.Ar devname 89is altered or displayed. 90.El 91.Sh FILES 92.Bl -tag -width /dev/urandomx -compact 93.It Pa /dev/random 94Returns ``good'' values only 95.It Pa /dev/urandom 96Always returns data, degenerates to a pseudo-random generator 97.El 98.Sh SEE ALSO 99.Xr rnd 4 , 100.Xr rnd 9 101.Sh HISTORY 102The 103.Nm 104program was first made available in 105.Nx 1.3 . 106.Sh AUTHORS 107The 108.Nm 109program was written by Michael Graff \*[Lt]explorer@flame.org\*[Gt]. 110.Sh BUGS 111Turning on entropy estimation from unsafe or predictable sources will 112weaken system security, while turning on entropy collection from such 113sources may weaken system security. 114.Pp 115Care should be taken when using this command. 116