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.Dd September 18, 2023 .Dt SAVE-ENTROPY 8 .Os .Sh NAME .Nm save-entropy .Nd Save bits of entropy to feed /dev/random at startup .Sh SYNOPSIS .Nm save-entropy .Sh DESCRIPTION The .Nm command is used to save entropy data from

a /dev/random to files in a specified output location. The files saved are used at startup to provide additional entropy for

a /dev/random . The output file will be different in every invocation until the maximum number of different files is reached. (See .Em entropy_save_num for details). By default this script is invoked via .Xr cron 8 every eleven minutes approximately.

p This command does nothing if executed inside a .Xr jail 8 .

p Three variables in

a /etc/rc.conf regulate the behavior of the script: l -tag -width Ds t Va entropy_dir Specify the directory for saved entropy files. Defaults to

a /var/db/entropy . If set to "NO" it disables caching entropy via .Xr cron 8 . This setting is shared with

a /etc/rc.d/random . t Va entropy_save_sz Size of the entropy cache files. Defaults to 4096. t Va entropy_save_num Number of entropy cache files to save. Defaults to 8. .El .Sh FILES l -tag -width Ds t Pa /etc/rc.conf .El .Sh EXIT STATUS .Ex -std Errors will be recorded in the system log. .Sh SEE ALSO .Xr syslog 3 , .Xr random 4 , .Xr rc.conf 5 , .Xr cron 8 .Sh HISTORY The .Nm command first appeared in .Fx 5.0 . .Sh AUTHORS The .Nm command was originally written by .An Doug Barton <dougb@FreeBSD.org> . This manual page was written by .An Fernando Apesteguia <fernape@FreeBSD.org> .