Either you need a trusted third party or you need to pass something that looks like (at best): 4UpbRAXYMgrESrAwiLPYymNNni1hwyL2JEK7zz2SN52t
You could do that by printing it on a business card or reading it over the phone, and then the other guy is going to have to type it in somewhere.
The reason trusted third party keeps on coming up, despite all the myriad fundamental problems, is exactly because slinging that around is so unattractive.
There IS a nicer way to present fingerprints to be much more human readable: map every few bytes to the whole dictionary word. There is a RFC for that:
You could do that by printing it on a business card or reading it over the phone, and then the other guy is going to have to type it in somewhere.
The reason trusted third party keeps on coming up, despite all the myriad fundamental problems, is exactly because slinging that around is so unattractive.