Stan Tobias <st...@privatdemail.net> wrote: >Yes, but by remote communication. The reasoning goes like this: The >signature is validated by my certificate (or, in case 2a, by my >friends' >whom I trust fully). The message is authenticated by X's valid >signature, >therefore the message has not been tampered with and its author is X. >X says he uses a new key K2. Because I've got this message from X, >I have verified the ownership of K2, so I can sign it.
Sorry, but this is wrong. The certificate of the first key is valid, the signature of the message is valid, but your correspondent's claim to ownership of the second key is not yet proven. While you know that whoever has control of the first key sent you that message, you have not confirmed that he can decrypt and sign with the second key. >> The idea of using a different channel for confirming key details such >as >> a key fingerprint is really a way of trying to avoid a >man-in-the-middle >> attack on the verification of the key and its UIDs. It is not >entirely >> foolproof--nothing is. > >I don't understand how man-in-the-middle fits here, I was explorig an >idea >if a trust (belief) once correctly initiated could later be transferred >purely remotely (electronically), without physical contact. I was commenting on why verification of key details outside of non-secure electronic channels prior to certification is useful rather than receiving a request electronically for you to certify a person's key and assuming it to be verification enough without using another channel to verify the request and purported key details. Cheers, --Paul -- PGP: 3DB6D884 _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
