rngd(8) [centos man page]

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] [-i, --ignorefail] [-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, --ver-
       sion]

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 forking on startup.  This is typically used  for  debugging.   The  -b	or
       --background options, which fork and put rngd into the background automatically, 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 --random-
       device options can be used to select an alternate entropy output device, besides the default /dev/random.  Note that this device must  sup-
       port the Linux kernel /dev/random ioctl API.

       FIXME: document random-step and timeout

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 (default: /var/run/rngd.pid)

       -i, --ignorefail
	      Ignore repeated fips failures

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

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

       -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 entropy
	      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 4							    March 2001								   RNGD(8)

Check Out this Related Man Page

RNDCTL(8)						    BSD System Manager's Manual 						 RNDCTL(8)

NAME

     rndctl -- in-kernel random number generator management tool

SYNOPSIS

     rndctl -CcEe [-d devname | -t devtype]
     rndctl -ls [-d devname | -t devtype]
     rndctl -L save-file
     rndctl -S save-file

DESCRIPTION

     The rndctl program displays statistics on the current state of the rnd(4) pseudo-driver, and allows the administrator to control which
     sources are allowed to contribute to the randomness pool maintained by rnd(4), as well as whether a given source counts as strongly random.

     The following options are available:

     -C      Disable collection of timing information for the given device name or device type.

     -c      Enable collection of timing information for the given device name or device type.

     -d      Only the device named devname is altered or displayed.  This is mutually exclusive with -t.

     -E      Disable entropy estimation from the collected timing information for the given device name or device type.  If collection is still
	     enabled, timing information is still collected and mixed into the internal entropy pool, but no entropy is assumed to be present.

     -e      Enable entropy estimation using the collected timing information for the given device name or device type.

     -L      Load saved entropy from file save-file, which will be overwritten and deleted before the entropy is loaded into the kernel.

     -l      List all sources, or, if the -t or -d flags are specified, only those specified by the devtype or devname specified.

     -S      Save entropy pool to file save-file.  The file format is specific to rndctl and includes an estimate of the amount of saved entropy
	     and a checksum.

     -s      Display statistics on the current state of the random collection pool.

     -t      All devices of type devtype are altered or displayed.  This is mutually exclusive with -d.

	     The available types are:

	     disk   Physical hard drives.

	     net    Network interfaces.

	     tape   Tape devices.

	     tty    Terminal, mouse, or other user input devices.

	     rng    Random number generators.

FILES

     /dev/random    Returns ``good'' values only.
     /dev/urandom   Always returns data, degenerates to a pseudo-random generator.

SEE ALSO

     rnd(4), rnd(9)

HISTORY

     The rndctl program was first made available in NetBSD 1.3.

AUTHORS

     The rndctl program was written by Michael Graff <explorer@flame.org>.

BUGS

     Turning on entropy estimation from unsafe or predictable sources will weaken system security, while turning on entropy collection from such
     sources may weaken system security.

     Care should be taken when using this command.

BSD
								 November 23, 2011							       BSD

Linux and UNIX Man Pages

rngd(8) [centos man page]

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