[plug] protecting a tar file

[Denis Brown]

Dear PLUG list members,

A final conundrum for tonight, concerning tar.   How does one protect
the contents of a tar file from being read by unauthorised people?   I'm
pretty sure I know the answer but this is a very inventive list so
there may be some simple yet effective solutions :-)

I can create a tar archive with something like tar --create --file
blah.tar dirname/ and all is sweet.   I then want to restrict access to
the tar file's contents so that it can be safely stored on a remote
server, say a Windows machine (don't ask!).   If the server gets cracked
and the tar file moved onto a hostile machine, can I set internally to the
tar file, permissions to prevent access to the archive contents?

The solution I had envisaged was GPG'ing the archive before sending it to
the server.   But is there an easier way using permissions, for example?
Some initial experimentation suggests not, but it never hurts to check.
Google has not been kind, neither have the man nor info pages for tar.
Closest I get that way is --same-user but that is not the ticket.

TIA,
Denis