.\" Copyright 2007, 2009 Colin Percival
.\" All rights reserved.
.\"
.Dd February 10, 2022
.Dt TARSNAP-KEYGEN 1
.Os
.Sh NAME
.Nm tarsnap-keygen
.Nd generate a key file for use with
.Xr tarsnap 1
.Sh SYNOPSIS
.Nm
.Fl -keyfile Ar key-file
.Fl -user Ar user-name
.Fl -machine Ar machine-name
.Op Fl -passphrased
.Op Fl -passphrase-mem Ar maxmem
.Op Fl -passphrase-time Ar maxtime
.Nm
.Fl -version
.Sh DESCRIPTION
.Nm
generates cryptographic keys, registers with the
tarsnap server, and writes a key file for use with
.Xr tarsnap 1 .
.Pp
The
.Fl -keyfile Ar key-file
option specifies the name of the file in which to write the newly-generated
keys.
The
.Fl -user Ar user-name
option specifies the name (i.e. email address) of the Tarsnap account.
The
.Fl -machine Ar machine-name
option specifies a name which will be displayed in accounting reports so that
you can see how much data each machine is storing.
.Pp
If the
.Fl -passphrased
option is specified, the user will be prompted to enter a passphrase (twice)
to be used to encrypt the key file.
.Pp
If the
.Fl -passphrase-mem Ar maxmem
option is specified, a maximum of
.Ar maxmem
bytes of RAM will be used in the scrypt key derivation function to
encrypt the key file; it may be necessary to set this option if a key
file is being generated on a system with far more RAM than the system
on which the key file will be used.
.Pp
If the
.Fl -passphrase-time Ar maxtime
option is specified, a maximum of approximately
.Ar maxtime
seconds will be used in the scrypt key derivation function to
encrypt the key file.
.Pp
The
.Fl -version
option prints the version number of
.Nm ,
then exits.