1.\" $NetBSD: rndctl.8,v 1.14 2002/10/03 15:41:45 wiz 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 1, 2002 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 CcEe 38.Op Fl d Ar devname 39.Op Fl t Ar devtype 40.Nm "" 41.Fl ls 42.Op Fl d Ar devname 43.Op Fl t Ar devtype 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 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 d 63Only the device named 64.Ar devname 65is altered or displayed. 66See also 67.Fl t . 68.It Fl E 69Disable entropy estimation from the collected timing information for 70the given device name or device type. 71If collection is still enabled, timing information is still 72collected and mixed into the internal entropy pool, 73but no entropy is assumed to be present. 74.It Fl e 75Enable entropy estimation using the collected timing information 76for the given device name or device type. 77.It Fl l 78List all sources, or, if the 79.Fl t 80or 81.Fl d 82flags are specified, only those specified by the 83.Ar devtype 84or 85.Ar devname 86specified. 87.It Fl s 88Display statistics on the current state of the random collection pool. 89.It Fl t 90All devices of type 91.Ar devtype 92are altered or displayed. 93See also 94.Fl d . 95.El 96.Sh FILES 97.Bl -tag -width /dev/urandomx -compact 98.It Pa /dev/random 99Returns 100.Dq good 101values only. 102.It Pa /dev/urandom 103Always returns data, degenerates to a pseudo-random generator. 104.El 105.Sh SEE ALSO 106.Xr rnd 4 , 107.Xr rnd 9 108.Sh HISTORY 109The 110.Nm 111program was first made available in 112.Nx 1.3 . 113.Sh AUTHORS 114The 115.Nm 116program was written by 117.An Michael Graff 118.Aq explorer@flame.org . 119.Sh BUGS 120Turning on entropy estimation from unsafe or predictable sources will 121weaken system security, while turning on entropy collection from such 122sources may weaken system security. 123.Pp 124Care should be taken when using this command. 125