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Re: Encryption question
From: "D.E. Chadbourne" <235u () comcast net>
Date: Wed, 03 Mar 2004 08:46:25 -0500

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Joerg Over Dexia wrote:
| Am 14:49 02.03.2004 +0100 teilte F.O. Bossert mir folgendes mit:
| ->But that is his point! Sending an Fake message with an fake
| hash, with
| ->real public key and fake private key,
| ->does give the receiver the false impression that the message is
| from Alice!

the person you're pretending to be needs a new fake key that you can
make others think it's you intended vic.  you can't use "part" of the
key combination.  here's a quote from
http://www.gnupg.org/gph/en/manual.html#CONCEPTS

"Key tampering is a major security weakness with public-key
cryptography. An eavesdropper may tamper with a user's keyrings or forge
a user's public key and post it for others to download and use. For
example, suppose Chloe wants to monitor the messages that Alice sends to
Blake. She could mount what is called a man in the middle attack. In
this attack, <read this slowly, it's important> Chloe creates a new
public/private keypair. She replaces Alice's copy of Blake's public key
with the new public key. She then intercepts the messages that Alice
sends to Blake. For each intercept, she decrypts it using the new
private key, reencrypts it using Blake's true public key, and forwards
the reencrypted message to Blake. All messages sent from Alice to Blake
can now be read by Chloe."

hope this helped.  GnuPG rules!
- -eric.

- --
Secure Linux Computing
http://235u.home.comcast.net/
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