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From: jrbd@craycos.com (James Davies)
Newsgroups: sci.crypt,comp.org.eff.talk
Subject: Re: Clipper considered harmful [Restated and amplified]
Message-ID: <1993Apr26.212222.19901@craycos.com>
Date: 26 Apr 93 21:22:22 GMT
References: <1993Apr22.222016.25628@lehman.com> <15583@optilink.COM> <1993Apr26.145937.3570@wdl.loral.com>
Organization: Cray Computer Corporation
Lines: 19

In article <1993Apr26.145937.3570@wdl.loral.com> koontzd@phobos.lrmsc.loral.com (David Koontz ) writes:
>>Clipper also allows an extraordinary opportunity for the criminal to
>>conceal use of super-encryption.  An automated full-system surveillance
>>mechanism (quite feasible across radio bandwidth) which knows family key F,
>>can validate Clipper wrappers and N:ESN associations, but it cannot reveal
>>in realtime the use of super-encryption, unless it knows all unit keys,
>>which we are being assured are only to be made available in two separate
>>pieces, upon specific wiretap-like order.
>
>The serial number will be in a 64 bit block, with a 34 bit filler.  Doesn't
>take a lot to check to see if that is correct.

Yes, but the extra encryption could be applied *before* the message
is encrypted by the Clipper, so that the wrapper would be fine, the
phone's serial number and the session key would be in the law-enforcement
field, etc., but the message wouldn't be readable even if the particular
Clipper's key were obtained from the escrow agents.  In fact, it shouldn't
even be possible to detect that a message has been double-encrypted without
a court order, right?
