GnuPG 2.0.17's gpgtar option

Werner Koch wk at
Fri Jan 14 09:27:46 CET 2011

On Thu, 13 Jan 2011 18:19, sindegra at said:
> Good to see 2.0.17 has been released, but I am somewhat mystified by the
> gpgtar option thing I saw at the end of ./configure. I have no idea what
> it is. Can anyone help me with this?

For many years we have gpg-zip which is a wrapper around tar and gpg to
be compatible with the pgpzip tool.  Now there are many users of GnuPG
on Windows boxes and they don't have this tool because there is no real
shell under Windows and not tar program.  However many of them want a
tool to do archiving and encryption in one step.

I looked around to find a compatible tar implementation for Windows
which is small enough, can be cross-build and compatible to the USTAR.
Not easy, the few available tar implementations are quite complex and
don't have clean code which can be modified to easily build on all
platforms.  Thus I decided to look at the specs and indeed tar is not
very complicated if you can leave out all the blocking code, special
file handling and the precautions you need to take when restoring files.
Gpgtar will only be used to feed the tarball via a pipe to gpg (or vice
versa).  Restoring is done to a new directory.  Special files are not
needed because it is for Windows and not intended as a general purpose
backup device.  No hardlinks, no symlinks, etc.

The current implementation works with Kleopatra (the KDE key manager)
and allows to encrypt entire directory hierarchies under Windows and
POSIX.  Due to the way Kleopatra works, gpgtar does not currently
implement piping to gpg and requires the use of --no-crypto switch.  It
is part of gpg4win 2.1.  It is merely a convenience tool for those who
dislike writing a small pipeline.



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