Encrypted Snapshotted Remote Backup Service

Colin Percival's program 'tarsnap' to be used as a part of his online encrypted
snapshotted backup service, currently undergoing paid private beta testing. 

"Beta", means two things in this particular case:
1. stable but not feature complete
2. new releases come out rapidly.  Please check for a newer release before
building the one here - see https://beta.tarsnap.com/download.html

An easy way to use the slackbuild on a newer version without editing:
VERSION="<latest version>" tarsnap.SlackBuild

Please note that this is only the client.  In order to use tarsnap, one must
subscribe to the Tarsnap service - see their website for details.