rngd

RNGD(8)                     System Manager's Manual                    RNGD(8)

NAME
       rngd - Check and feed random data from hardware device to kernel random
       device

SYNOPSIS
       rngd [-b, --background] [-f, --foreground]  [-o,  --random-device=file]
       [-p,  --pid-file=file]  [-r, --rng-device=file] [-s, --random-step=nnn]
       [-W, --fill-watermark=nnn] [-d, --no-drng=1|0] [-n, --no-tpm=1|0]  [-q,
       --quiet] [-v, --verbose] [-?, --help] [-V, --version]

DESCRIPTION
       This  daemon  feeds data from a random number generator to the kernel's
       random number entropy pool, after first checking  the  data  to  ensure
       that it is properly random.

       The  -f or --foreground options can be used to tell rngd to avoid fork-
       ing on startup.  This is typically  used  for  debugging.   The  -b  or
       --background options, which fork and put rngd into the background auto-
       matically, are the default.

       The -r or --rng-device options can  be  used  to  select  an  alternate
       source  of  input, besides the default /dev/hwrandom.  The -o or --ran-
       dom-device options can be used to select an  alternate  entropy  output
       device,  besides  the  default /dev/random.  Note that this device must
       support the Linux kernel /dev/random ioctl API.

OPTIONS
       -b, --background
              Become a daemon (default)

       -f, --foreground
              Do not fork and become a daemon

       -p file, --pid-file=file
              File used for recording daemon PID, and multiple exclusion  (de-
              fault: /var/run/rngd.pid)

       -o file, --random-device=file
              Kernel  device used for random number output (default: /dev/ran-
              dom)

       -r file, --rng-device=file
              Kernel device used for random number input (default: /dev/hwran-
              dom)

       -s nnn, --random-step=nnn
              Number of bytes written to random-device at a time (default: 64)

       -W n, --fill-watermark=nnn
              Once  we  start doing it, feed entropy to random-device until at
              least fill-watermark bits of entropy are available  in  its  en-
              tropy  pool  (default:  2048).  Setting this too high will cause
              rngd to dominate the contents of the entropy pool.   Low  values
              will hurt system performance during entropy starves.  Do not set
              fill-watermark above the size of the entropy pool (usually  4096
              bits).

       -d 1|0, --no-drng=1|0
              Do not use drng as a source of random number input (default:0)

       -n 1|0, --no-tpm=1|0
              Do not use tpm as a source of random number input (default:0)

       -q, --quiet
              Suppress error messages

       -v, --verbose
              Report available entropy sources

       -?, --help
              Give a short summary of all program options.

       -V, --version
              Print program version

AUTHORS
       Philipp Rumpf
       Jeff Garzik - jgarzik@pobox.com
       Matt Sottek
       Brad Hill

rng-tools 5                       March 2001                           RNGD(8)