rngd.8.in

   1 .\" Copyright (C) 2001 Jeff Garzik -- jgarzik@pobox.com
   2 .\"
   3 .TH RNGD 8 "March 2001" "@PACKAGE@ @VERSION@"
   4
   5 .SH NAME
   6 rngd \- Check and feed random data from hardware device to kernel random device
   7
   8 .SH SYNOPSIS
   9 .B rngd
  10 [\fB\-b\fR, \fB\-\-background\fR]
  11 [\fB\-f\fR, \fB\-\-foreground\fR]
  12 [\fB\-o\fR, \fB\-\-random-device=\fIfile\fR]
  13 [\fB\-r\fR, \fB\-\-rng-device=\fIfile\fR]
  14 [\fB\-s\fR, \fB\-\-random-step=\fInnn\fR]
  15 [\fB\-W\fR, \fB\-\-fill-watermark=\fInnn\fR]
  16 [\fB\-t\fR, \fB\-\-timeout=\fInnn\fR]
  17 [\fB\-?\fR, \fB\-\-help\fR]
  18 [\fB\-V\fR, \fB\-\-version\fR]
  19 .RI
  20
  21 .SH DESCRIPTION
  22 This daemon feeds data from a random number generator to the kernel's
  23 random number entropy pool, after first checking the data to ensure that
  24 it is properly random.
  25 .PP
  26 The \fB\-f\fR or \fB\-\-foreground\fR options can be used to tell
  27 \fBrngd\fR to avoid forking on startup.  This is typically used for
  28 debugging.  The \fB\-f\fR or \fB\-\-foreground\fR options, which fork and put
  29 \fBrngd\fR into the background automatically, are the default.
  30 .PP
  31 The \fB\-r\fR or \fB\-\-rng-device\fR options can be used to select an
  32 alternate source of input, besides the default /dev/hwrandom.
  33 The \fB\-o\fR or \fB\-\-random-device\fR options can be used to select
  34 an alternate entropy output device, besides the default /dev/random.
  35 Note that this device must support the Linux kernel /dev/random
  36 ioctl API.
  37 .PP
  38 FIXME: document random-step and timeout
  39
  40 .SH OPTIONS
  41 .TP
  42 \fB\-b\fR, \fB\-\-background\fR
  43 Become a daemon (default)
  44 .TP
  45 \fB\-f\fR, \fB\-\-foreground\fR
  46 Do not fork and become a daemon
  47 .TP
  48 \fB\-o\fI file\fR, \fB\-\-random-device=\fIfile\fR
  49 Kernel device used for random number output
  50 (default: /dev/random)
  51 .TP
  52 \fB\-r\fI file\fR, \fB\-\-rng-device=\fIfile\fR
  53 Kernel device used for random number input
  54 (default: /dev/hwrandom)
  55 .TP
  56 \fB\-s\fI nnn\fR, \fB\-\-random-step=\fInnn\fR
  57 Number of bytes written to random-device at a time (default: 64)
  58 .TP
  59 \fB\-W\fI n\fR, \fB\-\-fill\-watermark=\fInnn\fR
  60 Once we start doing it, feed entropy to \fIrandom-device\fR until at least
  61 \fIfill-watermark\fR bits of entropy are available in its entropy pool (default: 2048).
  62 Setting this too high will cause \fIrngd\fR to dominate the contents of the
  63 entropy pool.  Low values will hurt system performance during entropy
  64 starves.  Do not set \fIfill-watermark\fR above the size of the
  65 entropy pool (usually 4096 bits).
  66 .TP
  67 \fB\-t\fI nnn\fR, \fB\-\-timeout=\fInnn\fR
  68 Interval written to random-device when the entropy pool is full, in seconds, or 0 to disable (default: 60)
  69 .TP
  70 \fB\-?\fR, \fB\-\-help\fR
  71 Give a short summary of all program options.
  72 .TP
  73 \fB\-V\fR, \fB\-\-version\fR
  74 Print program version
  75
  76 .SH AUTHORS
  77 Philipp Rumpf
  78 .br
  79 Jeff Garzik \- jgarzik@pobox.com
  80 .br
  81 Matt Sottek
  82