fingerprint keys over ham radio:

[Welcome to Addendia, Mr. Lee. 23-Apr-1993 1109]

One thing to be careful of:  Amateur radio must *not* use codes or
cyphers to obscure meaning.  All information transmission must be in
the clear (not necessarily English, but no encryption of data).

The one exception is this:  codes and cyphers *may* be used to provide
checksumming, error correction, and/or authentication. (examples-
repeater control codes, autopatch codes, OSCAR control codes, etc. ) 

The meaning must still be in clear but you are allowed to send a
authenticating "signature" in code, as long as the signature 
contains no information other than authentication itself that was 
not also transmitted in clear.  That's why autopatch
protocol requires you to say "I'm turning on the patch" before you
transmit the (hopefully secret) autopatch control codes.

Please keep this in mind- and be able to prove it to the FCC should
they request it.  It might even be worth announcing the "authentication
only" mode at the start of your net, so both other amateurs and the
FCC itself know what to expect.  Posting software on a packet BBS
for others to download and verify a "no hidden codes" status would
probably be a reasonable action and a good protective measure.

	-Bill, N1KGX