From ebrandt at jarthur.Claremont.EDU  Wed Jul 21 12:54:42 1993
From: ebrandt at jarthur.Claremont.EDU (Eli Brandt)
Date: Wed, 21 Jul 93 12:54:42 PDT
Subject: subliminal messages
In-Reply-To: <9307210117.AA05181@snark.shearson.com>
Message-ID: <9307211953.AA16773@toad.com>


> A very good posting, Karl, but I will note in the literature these are
> called "covert" channels, not "subliminal" channels.

Covert channels are signaling techniques which bypass secrecy
classification, right?  e.g. twiddling with free disk and other
system parameters.  Passing messages in digital signatures, which
I've always seen called "subliminal channels", could of course be
used as a covert channel if the OS permits signatures on material
accessible to lower-classification folk.

> Perry

   Eli   ebrandt at jarthur.claremont.edu