Man page - rngd(8)

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Manual

RNGD

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
AUTHORS

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