In Message Wed, 23 Dec 92 13:18:54 PST, uunet.uu.net!ghsvax!hal@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 the signature.

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! nobody saw DrZaphod [AC/DC] / [DnA][HP] [drzaphod@ncselxsi.uucp] Technicolorized