[Dvdrtools-users] Re: crypt ISO image -- I'm not using afio, but afio is _cake_ to do ...

[Bryan J. Smith]

On Sat, 2003-01-25 at 11:39, André Dalle wrote:
> And as Bryan says, it is not as vulnerable to disc i/o errors.  I've
> never used CD/DVD for backup purposes for these reasons; but then most
> Linux and home users don't have access to network backups.

Not true!

Hence the inherit capabilities of rsh (and ssh).  E.g.:

   # find . -depth -mount -print \
   > | afio -ovZP lzop -M 64m /dev/stdout \
   > | rsh myserver buffer -m 10240000 -o /dev/st0

That creates an "afio" archive ("cpio" compatible, with per-file
compression) on remote system "myserver" tape drive, using the "buffer"
program on the remote system to buffer writing to the drive in ~10MB
chunks.

If you just want to create a file on a remote system, it's easier:

   # find . -depth -mount -print \
   > | afio -ovZP lzop -M 64m /dev/stdout \
   > | rsh myserver ~/myarchive.afio

Buffering is not necessary when writing to disk.

> Now on the other hand, I do have a handful of files that are
> sensitive, and that I do not want sitting on a remote backup
> server.  For myself, the filenames themselves are inconsequential,
> but the dir/file obscurity is still a nice feature in that a data
> thief would not be able to guess as to the contents.
> Perhaps back2cd with MD5/GPG crypto is a viable solution.
> Bryan, from a previous thread you mentioned this script - it is
> designed to slurp in a directory, which could be '/', generate
> an afio archive, and make an ISO of that?

That's actually too simple for my script, which does all kinds of
per-file stuff, which is where the "complexity" comes in (resulting in
200+ lines).

You could write your own script to do such in about 10 lines.  3-step
Pseudo code:
   find | afio
   encrypt
   mkisofs

Simple, no???

> Just checking the afio manpage, could this be a problem:
> Cannot archive of files larger than 2 GB, even if compiled
> with large filesystem support.   
> (Pre-2.4.7  versions of afio did not deal with this problem
> gracefully, see HISTORY file for details.)
> I think the archive itself can be 2+GB, just not any single file
> in the archive.

But "afio" _does_ offer:

      −s size      Restrict each portion of a multi‐volume  archive
                   to size characters.

So you can make multiple, _independent_ afio archives of "size".  This
is very cool for CD.  And _unlike_ split, they _are_ 100% independent --
you don't need the first, nor any other "part" upto "X" to extract from
"part X".

So for DVD, you could create multiples of 2GB or so.  Or, actually,
1.5GB might be ideal, because you would then place upto 3 per DVD.


-- 
Bryan J. Smith, E.I. (BSECE)       Contact Info:  http://thebs.org
[ http://thebs.org/files/resume/BryanJonSmith_certifications.pdf ]
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