NAME

save-entropy — Save bits of entropy to feed /dev/random at startup

SYNOPSIS

DESCRIPTION

The save-entropy command is used to save entropy data from /dev/random to files in a specified output location. The files saved are used at startup to provide additional entropy for /dev/random. The output file will be different in every invocation until the maximum number of different files is reached. (See entropy_save_num for details). By default this script is invoked via cron(8) every eleven minutes approximately.

This command does nothing if executed inside a jail(8).

Three variables in /etc/rc.conf regulate the behavior of the script:

entropy_dir

Specify the directory for saved entropy files. Defaults to /var/db/entropy. If set to "NO" it disables caching entropy via cron(8). This setting is shared with /etc/rc.d/random.

entropy_save_sz

Size of the entropy cache files. Defaults to 4096.

entropy_save_num

Number of entropy cache files to save. Defaults to 8.

FILES

/etc/rc.conf

 

EXIT STATUS

The save-entropy utility exits 0 on success, and >0 if an error occurs. Errors will be recorded in the system log.

SEE ALSO

syslog(3), random(4), rc.conf(5), cron(8)

HISTORY

The save-entropy command first appeared in FreeBSD 5.0.

AUTHORS

The save-entropy command was originally written by Doug Barton <dougb@FreeBSD.org>. This manual page was written by
Fernando Apesteguia <fernape@FreeBSD.org>.