Remember that ham radio transmissions can't be encrypted.

Cheerful regards,

Bob


> > Yes, but one can also record an encrypted message and play it over and=
=20
> > over
> > again.
> >
> > The only way I can think of is signing/encrypting the message and=20
> > including
> > a message number counter on the message. The server and client both kee=
p
> > track of the message number and increment it each time. If a replayed
> > message is arrived, it won't be valid because it would have an old mess=
age
> > number.
> >
> > I assume that if the message is signed and the message number is
> > manipulated by a third party, the whole message-signature complex will =
be
> > detected as invalid by GPG verification.
>=20
> Just include a date-time stamp in the message before encryption and
> signing.

--=20
http://www.fastmail.fm - Access your email from home and the web

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.