[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
>correction.

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.