Signing text messages...
ncselxsi!drzaphod at ncselxsi.netcom.com
Wed Dec 23 16:16:27 PST 1992
In Message Wed, 23 Dec 92 13:18:54 PST,
uunet.uu.net!ghsvax!hal at netcomsv.netcom.com (Hal Finney) writes:
>Or are you suggesting that someone else could create a bogus public
>key claiming to mine, re-sign the message using that public key, and
>then get people to think it was from me?
Perhaps they could alter the message, use a bogus public key, and
re-sign the message.
>But no, I wouldn't, because people would (or should) know not to trust
>a random public key to be from whom it claims. My posted key is
>signed by Phil Zimmermann. This doesn't absolutely prove it is from
>me, but I think it makes it worthwhile to post the key.
I didn't realize you had included a signed key. Minus one point
for research. Yes, people SHOULD know not to use a publicly posted
key. But do they?
>Anyway, the real reason I posted the key in this case was so that
>people could check the cleartext signature to see if it had been
>mangled by various mail gateways. That was the topic of discussion in
>the message, so I wanted to make it easy for people to try checking
Then posting your public key was clearly the right thing to do. I
have noticed; however, that people have posted their public key
along with a signed message before [there was a discussion on mangled,
signed plaintext] and thought I would mention this to anybody who
thought they were using infallible methods or authentication.
I must urge everybody not to accept any key from a source other then
person to person [or using a fone call to exchange MD5 hashes] unless
it is signed by smoebody you HAVE exchanged keys with in this way.
I hope nobody sees a message with a public key attached to it and says,
"Oh! There's a key I can add to my keyring", and abandons the entire
key-exchange method. TTFN!
[AC/DC] / [DnA][HP]
[drzaphod at ncselxsi.uucp]
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