Army signals security & "Clansmen" series radios

[Charles Lindsey]

	On Fri, 8 Sep 2000 23:51:39 +0100
	"Owen Lewis" <oml@eloka.demon.co.uk> said...

> A second consideration is a single desk (appointment) may have as many as
> three occupants every 24 hours. In war (which is what the whole organisation
> is about) it is by no means impossible that there will be a dozen occupants
> of a single appointment in as little as a week. Some changes will be planned
> and others will be ad hoc.

So the secret key (whether it be symetric or asymetric) belongs to the "desk". 
If Captain A and Sergeant B and Corporal C are to be allowed to use the key, 
then the "desk" should hold certificates ensuring that the key may only be 
accessed (for use, not for copying) if A, B or C, as the case may be, can 
correctly sign a challenge with his own private key (observe this is much better 
than protecting the secret key with a passphrase because the passphrase does not 
need to be shared - if you like, there are three passphrases, and more can be 
created as needed).

Now if Sergeant B and Corporal C both get killed, then Captain A (or, in his 
absence, Major D) can create a new certificate for Private E. Naturally, the 
"desk" also holds certificates authorising Captain A and Major D to issue fresh 
certificates of the first kind (and to revoke existing ones, of course).

Note that this is also the proper way for corporate keys to be accessed in the 
business environment.

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