How to split up gpg data into multiple volumes?

[Ben Escoto]

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>>>>> "DC" == Daniel Carrera <dcarrera@math.toronto.edu>
>>>>> wrote the following on Wed, 7 Aug 2002 19:44:54 -0400 (EDT)

    ...
  DC> This makes guessing information much more difficult ("is it a
  DC> small file with little redundancy or a large file with lots of
  DC> redundancy?").

  DC> I don't think you have much to worry.

  DC> However, if you wish to have the files the same size, perhaps
  DC> you could add some garbage data at the end of the original
  DC> files.

Thank you for the reply.  I realize there probably isn't much real
risk, but I am writing a backup program (see
http://rdiff-backup.stanford.edu/duplicity) so I wanted to try to
cover all the bases in case it would be a problem for someone.

    About the writing garbage data at the end, that is a good idea.
I believe it is part of the tar standard to ignore any data past a
block of nulls.  So I could just add garbage (incompressible data) to
the end of the tar to fill it out, and assume that, say, 8kB of
garbage will extend the gpg file by 8kB.

    Things will still look a bit sloppy since all the volume sizes
will be slightly different, but I don't think anyone could complain
about information getting leaked out.  Thanks for the suggestion,
seems very reasonable.

    (Of course, coming up with uncompressible data might be a chore..
I suppose I could try recycling the gpg output..)


-- 
Ben Escoto

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