burden of proof / keys or plaintext (Re: US Plans for

[Charles Lindsey]

	On Thu, 5 Aug 1999 06:56:19 +0100
	David Swarbrick <david@swarb.demon.co.uk> said...

> 
> 
> In message <199908042053.VAA05266@clw.cs.man.ac.uk>, Charles Lindsey
> <chl@clw.cs.man.ac.uk> writes
> >
> >If the spooks want to demand the session keys of messages in which
> >they are "interested", then it is only necessary to provide the header
> >of the suspect message to the man who has the private key (the bit
> >which containes the session key encoded with the public key). It is not
> >necessary for him to be provided with the whole message.
> >
> But the bill imposes no obligation to ask only for a session key, or
> indeed only for plaintext. They can ask for the keys - whatever keys are
> necessary for their purpose.

Sure. I was just discussing what the Bill OUGHT to say (or what it might
in due course say if we continue pressing).
> 
> 
> He would not need ever to see the message either. He can just be told
> 'gimme the key'

No, the warrant holder has to identify the key which is being asked for.
He might do it by providing some known public key, and asking for the
matching private one, or else he might do it by providing some message
(or the header of some message) and asking for the key required to
decrypt it (or one of the possibly several keys that might decrypt it).

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