🚀 go-pugleaf

Thus said denning@guvax.acc.georgetown.edu:
>You can get even more security by using Silvio Micali's "fair 
>public-key cryptosystem" approach.  Called "fair" because it is 
>designed to strike a balance between the needs of the Government and
>those of the citizens.  With his approach, you would break your key
>up into 5 parts and give it to different trustees.  All 5 parts
>are needed to reassemble it, but it is possible to veryify the parts
>individually and as a whole without putting them together -- 
>ingenious!  He presented this at CRYPTO '92. 

A reasonable idea, but unfortunately it is subject to the same problems
as a single trustee:  There is no way to "prove" that someone is using
an unregistered key until you get probable cause and get a court order
for the keys and discover that you can't decrypt the traffic.  (Assuming
you can tell that you can't decrypt, maybe the data is incomprehensible
anyway...)  Then you subpoena the person to explain what the traffic
*means*, in which case you may as well have used the subpoena to obtain
the key in the first place.

The only real "solution" to this that I know is to require a trusted
third party that *generates* your key, gives you the private portion,
publishes the public portion, and keeps the private portion (possibly
encrypted with a DOJ key or something) in escrow.  Obviously this
requires *total* trust in this third party, and doesn't lend itself well
to multiple third parties.
-- 
Marc VanHeyningen    mvanheyn@whale.cs.indiana.edu    MIME & RIPEM accepted
A good rule of thumb to keep in mind is that anything that calls itself
`science' probably isn't.
	- John "I don't know about minds, but I know what I like" Searle