[wellylug] Encrypted backup recovery

David Antliff dave.antliff at paradise.net.nz
Tue Aug 24 17:22:12 NZST 2004


On Mon, 23 Aug 2004, Kevin Dorne wrote:

> Does anyone know of an encryption scheme that can (to some degree)
> recover from read errors on the disk?

I'm guessing what you really want to do is encrypt them and *then* apply
some sort of redundant encoding to the encrypted file(s). It might be
easier to think of it in this way - forget trying to find something tied
up with encryption and just look for a way of injecting redundant
information. I don't really know of any specifically for that task but you
suggest that bzip2 can cope with some errors? Why not bzip2 the encrypted
file then?

Do any of those ASCII encodings (MIME) pad out with redundant information?
Maybe there's something that can add parity? The encryption just clouds
the issue, if I understand what you're trying to do properly.

Also, if DVD formats are anything like CDROM, you get redundancy just by
writing to disk anyway - the interleaving and encoding on a CDROM is
pretty robust.

Or you could just put the encrypted file on the disk twice? Or better yet,
on two different disks? There should be enough redundancy there to recover
your information even if one disk is completely destroyed! ;)


-- 
David.




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