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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] [-t, --timeout=nnn] [-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 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 support the Linux kernel /dev/random ioctl API.

OPTIONS

Become a daemon (default)
Do not fork and become a daemon
Ignore repeated fips failures.
File used for recording daemon PID, and multiple exclusion (default: /var/run/rngd.pid)
Kernel device used for random number output (default: /dev/random)
Kernel device used for random number input (default: /dev/hwrandom)
Number of bytes written to random-device at a time (default: 64)
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).
Do not use drng as a source of random number input (default:0)
Do not use tpm as a source of random number input (default:0)
Interval written to random-device when the entropy pool is full. Note that this option exists for backward compatibility in RHEL6, but is ignored. Rngd now correctly waits until writing to a random-device will not block.
Suppress error messages
Report available entropy sources
-?, --help
Give a short summary of all program options.
Print program version

AUTHORS

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

March 2001 rng-tools 5