From: tcmay@netcom.com (Timothy C. May)
Subject: Re: Once they get your keys....
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
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(alt.security.clipper added, to keep them informed of this issue)


David Sternlight (strnlght@netcom.com) wrote:
....
: The proposal could be modified so that if they get a court order to tap you
: and don't charge you with a crime within, say, 90 days, they have to buy you
: a new phone.
: 
: If they do charge you, and you are found innocent, they have to buy you a
: new phone.
: 
: :-)

Yes, but will they buy you a ticket on a time machine to allow you to
go back and use the phone with the new key instead of the phone whose
key they obtained?

It is unclear whether obtaining the key at time 0 also unlocks
messages recorded (by whomever) at earlier times. The announcement was
silent on this. The betting seems to be that once your key has been
obtained (by the authorities, by divorce lawyers, by the Mafia, by the
FBI, by lost or stolen backup tapes, by the NSA, etc.). all previous
conversations are unsecure. (Session keys are negotiated, but knowing
the private key is believed by many commentators here to break the
security. No doubt more details will emerge.)

So, the loss of a key, whether one is guilty or innocent, may mean a lot
more than merely replacing the phone.

Sort of like saying to someone, "Oh, I copied your diary. But I'll buy
you a new one."


And the system, if made mandatory (as I expect), will make such
storing of conversations much easier, I fear. For one thing, the
transmission of the escrow key field acts as a clear signal to anyone
listening, a kind of "Caller ID" and "Callee ID" on a grand scale.
Also, the phone companies may not care as much about protecting the
privacy of the calls, as they perceive them all to be useless
encrypted junk. (This is a bit of a reach, I know, suggesting that the
Clipper will make security more lax...).

Anyway, still lots of issues unresolved.


-Tim May


-- 
..........................................................................
Timothy C. May         | Crypto Anarchy: encryption, digital money,  
tcmay@netcom.com       | anonymous networks, digital pseudonyms, zero
408-688-5409           | knowledge, reputations, information markets, 
W.A.S.T.E.: Aptos, CA  | black markets, collapse of governments.
Higher Power: 2^756839 | Public Key: PGP and MailSafe available.

