security issue with signing files

[Anthony E. Greene]

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On Sat, 24 Nov 2001, Florian Weimer wrote:
>I don't think both scenarios (local copy vs. in-memory copy) make much
>of a difference.  If an attacker is able to fiddle with my files, in
>almost all but a few constructed cases, he can also take over my
>account, grab the secret key, and eavesdrop the passphrase.

We're not talking about a deliberate attack here. This is about
inadvertantly signing a document that has changed without your knowledge.  
The change was made by an authorized user; you just hadn't see the change
when you signed the document.

The document is shared but your keys may not be on a shared resource. So
your keys may not be vulnerable at all. This is a real problem that cannot
be hand-waved away. The solution is simple, but it is something that
signers should be aware of.

Tony
- -- 
Anthony E. Greene <agreene@pobox.com> <http://www.pobox.com/~agreene/>
PGP Key: 0x6C94239D/7B3D BD7D 7D91 1B44 BA26 C484 A42A 60DD 6C94 239D
Chat: AOL/Yahoo: TonyG05
Linux. The choice of a GNU generation <http://www.linux.org/>

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