Re: Any protection against 'bit rot' ?

[Joachim Schipper <joachim@joachimschipper.nl>]

On Tue, Nov 23, 2010 at 12:48:58PM +0100, Johan Brinch wrote:
> On Tue, Nov 23, 2010 at 12:45, Andy <tarsnap-users@orgdotuk.org.uk> wrote:
> >> A 2048-bit RSA key used for signing archives. This is used in combination with SHA256 and a Merkle hash tree to verify the authenticity of stored archives.
> >
> > So presumably any time an archive is accessed, corruption could be
> > detected - but corrected?
> 
> I don't think tarsnap can correct the errors, considering the data is
> encrypted. A bit flip in one block would corrupt everything when
> decrypting. Detection should be OK due to hashes, though.

I don't think Tarsnap *does* correct the errors, but it's not impossible
to use an error-correcting code on top of an encryption algorithm.

I'm not sure Amazon doesn't already do some form of error correction,
though.

		Joachim