[E-Lang] Summary for Practical Programming

Bill Frantz frantz@communities.com
Mon, 05 Feb 2001 12:40:33 -0800

At 11:39 AM 2/5/01 -0500, Jonathan S. Shapiro wrote:
...Tyler and Jonathan's list of covert channels snipped...
>Regrettably not. The disk arm, the external interrupt sources, the
>ageing mechanism.... Basically, any source of a "clock" (by which is
>meant in this context a linear sequence of probabilistically
>distinguishable events) is a potential covert channel source. If the
>sequencing is only statistically detectable, you need to add error

The ability of aggressive error correction to allow communication under
very unfavorable circumstances should not be underestimated.  Spacecraft
communication is probably the most familiar example.