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Re: md5sums files

Russ Allbery wrote:

> Wouter Verhelst <wouter@debian.org> writes:
> > Or is it useful to be able to say "if it doesn't check out, it's
> > certainly corrupt, and if it does check out, it may be corrupt"? Didn't
> > think so.
> I don't understand why you say this.  Cryptographic attacks on MD5 aren't
> going to happen as a result of random file corruption.  The MD5 checksums
> are still very effective at finding file corruption or modification from
> what's in the Debian package unless that modification was done by a
> sophisticated attacker (MD5 preimage attacks are still not exactly easy).
> Detecting compromises is useful, but only a small part of what the MD5
> checksums are useful for.

If the machine has been compromised, *nothing* on the machine can be
trusted, whether its gpg signed or not. However, for detecting corruptions
and the local sysadmin meddling Russ mentioned, md5sum is more than adequate
and using something 'more secure' than md5sum is overkill.

Erik de Castro Lopo

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