Army signals security & "Clansmen" series radios

[Charles Lindsey]

	On Wed, 6 Sep 2000 17:23:30 +0100
	"David Howe" <DHowe@Hawkswing.demon.co.uk> said...

> That preassumes one key==one recipient. there is no real reason you can't
> have a hierarchy of keys - one per ship, one per flotilla, one per taskforce
> transmitted using the more granular keys when the taskforce is set up. You
> can then factor in your groupings by using the largest possible key that
> doesn't contain a non-recipient (so, you could send to two flotillas, and to
> three ships that aren't in a flotilla that is effected but should know
> anyhow)
> The downside is traffic analysis - if you suddenly notice three ships and
> two flotillas getting shared encypted traffic, you might start looking for
> connections. however, if you lose the key material on a given ship, you
> compromise (at worst) the groupings that ship is a member of, not the navy
> as a whole.

Quite so. I am sure the military people have been round those arguments
many times.

Charles H. Lindsey ---------At Home, doing my own thing------------------------
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