From: "Karl L. Barrus" <barrus@tree.egr.uh.edu> writes:
You posted some very good questions. The reason why it is "unacceptable" to accept keys electronically is that you may be vulnerable to spoofing. Okay, in reality, you have to realize that attacking cryptographic protocols is a paranoid view of things, and that you may not be attacked, but... if you send your public key to somebody, it could be possible for someone to eavesdrop, grab your key, substitute their own, and send that one along. Then when someone responds to "you", the eavesdropper could read the message, re-encrypt it with the public key they stole, and send it along to you. Then, you don't even know you are the victim of eavesdropping.
But we both call the same system (at least the people I x-change keys with) usually mindvox or a private system with a respected name... and in the case of Minvox, we do a DCC on IRC... straight person-to-person... to be eavesdropping... one, they'd have to tap my line, heavy equipment needed to tap a 16.8k HST v.42bis connection, seeing as I pretty much max out a phone line and HST's are really picky... or two, they'd intercept a DCC on the IRC at berkeley... but that's a 57.6k connection... however, that does seem possible... does anyone have any suggestions on how to make e-transfers of keys more secure, because, besides snail-mail (which would please the feds a lot) I have no other way of getting my key to them...
Anyway, it all boils down to validating the keys you receive. Which makes it tough unless you can meet people face to face. However, the latest version of pgp contains an option which computes the md5 hash of your public key - which allows you to call someone, and read each others hashes, thus completing the verification over the phone. Of course, now you have to worry about receiving their correct phone number... :-)
geez, I didn't know it was this complicated... if someone screws with the key, it just doesn't decode, correct? nowadays, with MNP and ARQ-retries and all of our little .bis buddies, not to mention the CRC's in transfer protos, wouldn't that make an error in transfer EXTREMELY remote... so the only other way'd be tampering and even then it just wouldn't decode, so what... you get the key again... but I oversimplify the situation, I guess... Oh, and I know this is going to make me sound like a complete idiot in front of my peers, but I've always did straight tranfers of keys... how do you put ascii keys into your keyring? I can't seem to make MacPGP do it... sniffle... and if ihe reason I can't decode the key is due to an error in transmission, forget this entire message... +-------Matt-Willis--------------------------------+ | Matt Willis ASTMWILL@STETSON.BITNET | elsewhere: | Matt Willis Head of the Underground | mwill@mindvox.phantom.com | Matt Willis Robotech PBM List | +-------Matt-Willis--------------------------------+ "Absolutely alone in awareness of the mechanism." -Agrippa by WG