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

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 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

-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)
-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
March 2001 rng-tools 5