Re: BBS E-mail policy

Eric, count this as another vote for default encryption of all
communications links.  

Omega: the way to tell is to run a frequency count on the text.  If it
follows the usual distribution for the language it's in, then it's probably
plaintext.  In which case the BBS rejects it.  

Voice: yeah, it's a pain in the tail. One thing I thought might be
interesting is to use two digitisers: one for the voice input, another for a
keystream which is derived from a radio or TV program signal which can be
picked up simultaneously by both correspondents.  XOR the two streams
together and then do whatever you have to do to make the encrypted results
transmissable.  I actually tried building an analog version of this about
ten years ago (might even bring it to one of our meetings, just for fun).
Analog voice "encryption" is actually pretty worthless (I didn't know how
worthless until I experimented with it) from a security standpoint.  

Voiceprint modification may have some uses.  About five or six years ago I
built one of those: based on a pitch shifter with a graphic EQ on the input
side and another on the output side.  Worked, sort of.  Now there is a
phone you can buy with something similar built in.  

-gg

>From: George A. Gleason <gg@well.sf.ca.us>

>Voice: yeah, it's a pain in the tail. One thing I thought might be
>interesting is to use two digitisers: one for the voice input, another for a
>keystream which is derived from a radio or TV program signal which can be
>picked up simultaneously by both correspondents.  XOR the two streams
>together and then do whatever you have to do to make the encrypted results
>transmissable.

Its so simple to just built fully digital systems that use real public
key encryption, I don't see why anyone would want to use something
like you are proposing. Your system would provide virtually no real
security.

I really suggest that anyone who is serious about doing this stuff
read unabridged (hardcover only) version of "The Codebreakers" by
Kahn. He gets into lots of historical examples of how stupidly
designed cryptosystems have cost people their lives. Ususally, people
have very poor ideas of what is and isn't secure. I suggest that some
historical perspective may give people more respect for how hard it is
to do this stuff right.

Perry