| random.4 (72929) | random.4 (73378) |
|---|---|
| 1.\" Copyright (c) 2001 Mark R V Murray. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright --- 7 unchanged lines hidden (view full) --- 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" | 1.\" Copyright (c) 2001 Mark R V Murray. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright --- 7 unchanged lines hidden (view full) --- 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" |
| 24.\" $FreeBSD: head/share/man/man4/random.4 72929 2001-02-23 01:12:44Z green $ | 24.\" $FreeBSD: head/share/man/man4/random.4 73378 2001-03-03 14:21:58Z markm $ |
| 25.\" 26.Dd February 10, 2001 27.Dt RANDOM 4 28.Os 29.Sh NAME 30.Nm random 31.Nd the entropy device 32.Sh DESCRIPTION --- 13 unchanged lines hidden (view full) --- 46then closing the device after writing 47will make the internal generator reseed itself. 48This can be used for extra security, 49as it immediately introduces any/all new entropy 50into the PRNG. 51The 52.Nm 53device can be controlled with | 25.\" 26.Dd February 10, 2001 27.Dt RANDOM 4 28.Os 29.Sh NAME 30.Nm random 31.Nd the entropy device 32.Sh DESCRIPTION --- 13 unchanged lines hidden (view full) --- 46then closing the device after writing 47will make the internal generator reseed itself. 48This can be used for extra security, 49as it immediately introduces any/all new entropy 50into the PRNG. 51The 52.Nm 53device can be controlled with |
| 54.Xr sysctl 8 . | 54.Ic sysctl . |
| 55.Pp 56To see the devices' current settings, use the command line: 57.Pp 58.Dl sysctl kern.random 59.Pp 60which results in something like: 61.Pp 62.Bd -literal -offset indent --- 41 unchanged lines hidden (view full) --- 104The 105.Va kern.random.sys.harvest_interrupt 106variable is used to select hardware interrupts 107as an entropy source. 108A zero (0) value means interrupts 109are not considered as an entropy source. 110Set the variable to one (1) 111if you wish to use them for entropy harvesting. | 55.Pp 56To see the devices' current settings, use the command line: 57.Pp 58.Dl sysctl kern.random 59.Pp 60which results in something like: 61.Pp 62.Bd -literal -offset indent --- 41 unchanged lines hidden (view full) --- 104The 105.Va kern.random.sys.harvest_interrupt 106variable is used to select hardware interrupts 107as an entropy source. 108A zero (0) value means interrupts 109are not considered as an entropy source. 110Set the variable to one (1) 111if you wish to use them for entropy harvesting. |
| 112Currently, 113only hard disk controllers 114are considered as interrupt entropy sources. | 112All interrupt harvesting is setup by the 113individual device drivers. |
| 115.Pp 116The other variables are explained in the paper describing the 117.Em Yarrow 118algorithm at 119.Pa http://www.counterpane.com/yarrow.html . 120.Sh FILES 121.Bl -tag -width /dev/random 122.It Pa /dev/random 123.El | 114.Pp 115The other variables are explained in the paper describing the 116.Em Yarrow 117algorithm at 118.Pa http://www.counterpane.com/yarrow.html . 119.Sh FILES 120.Bl -tag -width /dev/random 121.It Pa /dev/random 122.El |
| 123.Sh SEE ALSO 124.Xr sysctl 8 |
|
| 124.Sh HISTORY 125A 126.Nm 127device appeared in 128.Fx 2.2 . 129The early version was taken from Theodore Ts'o's entropy driver for Linux. 130The current implementation, 131introduced in 132.Fx 5.0 , 133is a complete rewrite by | 125.Sh HISTORY 126A 127.Nm 128device appeared in 129.Fx 2.2 . 130The early version was taken from Theodore Ts'o's entropy driver for Linux. 131The current implementation, 132introduced in 133.Fx 5.0 , 134is a complete rewrite by |
| 134.An Mark Murray , | 135.An Mark R V Murray , |
| 135and is an implementation of the 136.Em Yarrow 137algorithm by Bruce Schneier, 138.Em et al . | 136and is an implementation of the 137.Em Yarrow 138algorithm by Bruce Schneier, 139.Em et al . |