[Digikam-users] backup and data integrity
Jakob Østergaard Hegelund
joe at evalesco.com
Wed Jan 23 08:22:42 GMT 2008
On Tuesday 22 January 2008, Arnd Baecker wrote:
> On Mon, 21 Jan 2008, Gerhard Kulzer wrote:
>
> [...]
>
> > Arnd, can you send me the script? I'd like to try too.
>
> Done (off-list, it is really not ment for general consumption ... ;-)
>
> > I just read that strigi is exactly doing what we want, comparing
> > files with sha1. Maybe sha1 is faster than md5?
>
> No idea. Maybe we should do a speed test at some point ;-)
Both sha1 and md5 are designed to make it difficult to create a file
with a specific checksum. This is necessary for applications like
digital signatures, but it usually comes at a significant performance
(and complexity) premium.
CRCs, on the other hand, were meant to catch what you're trying to
catch, and will usually be a lot faster.
A CRC64 should be more than sufficient to catch any of the mismatches
you're looking for (CRC32, such as reported by the cksum command, would
probably be good enough for most purposes as well). And it will
definitely be much much faster than the cryptographically secure
hashes.
--
Jakob Østergaard Hegelund
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