From: dstalder@gmuvax2.gmu.edu (Darren/Torin/Who ever...)
Date: Thu, 22 Apr 93 00:54:38 PDT
To: ggoebel@sun1.ruf.uni-freiburg.de (Garrett Goebel)
Subject: Non-Technical description of problems with wiretap chip
Message-ID: <9304220755.AA00743@gmuvax2.gmu.edu>
MIME-Version: 1.0
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The WIRE-TAP Proposal:  Problems with it.

The White House sent out a press release on Friday 16 April about a voice
encryption chip called the Clipper chip.  This has come to be known as the
Wiretap chip since it allows any Law Enforcement agency to automatically
decrypt any conversations made with it with a search warrant.  The LE
presents said search warrant to two different escrow agencies to obtain the
keys (80 bits long) that automatically decrypts your conversation.  The
Electronic Frontier Foundation (EFF) and the Computer Professionals for
Social Responsibility (CPSR) have both criticized the proposal.  There was
even a negative article already in Network World (19 Apr 93).  The
paragraphs that follow are facts and problems I have collected by listening
to other discuss the Wiretap chip.

Say you wanted to encrypt your talk with someone over a phone.  Well, since
you and the person you want to talk to both have the Wiretap (Clipper) chip
in your phones, you can automatically encrypt your conversation.  All fine
and good encryption for the consumer.  Now, what if you come under
investigation by the local constabulary?  The get a court order and ask the
escrow agencies (non-law enforcement types) for your key.  They already
have the family key since that is the same in each chip.  They now have
your specific key.  With these two keys, they can decrypt all conversations
that you have.  This includes conversations that are not legal to wiretap
such as attorney-client, doctor-patient and so on.  They also have that key
for any all future sessions that you use that phone for.  Start to see the
problem?  This part is all legal...  Search warrants are even exceedingly
easy to get at times.  There have been reports of the FBI get groups of 50
signed and blank search warrants from the DoJ.

Now, there are other problems.  Would you give the IRS keys to your house
and filing cabinet as long as they promised that they would only use it
under proper authorization?  The key length of 80 bits is still considered
cryptographically weak.  The cryptographic algorithm is also being kept
classified.  This is not the usual practice.  In the cryptographic
community, algorithms are public.  This way people can be assured there
aren't any back doors and that the algorithm can stand on its own
strengths, not that of secrecy.  It is clear from the description that the
plan for key registration would be compromised if the algorithm was made
public; anyone could make chips or software that implemented it, using
their own keys.  These keys, of course, would not be registered.  It is not
that difficult to reverse engineer a chip these days.  It may also be true
that the algorithm itself is too weak to be shown to the public.  This was
true of a digital cellular encryption standard (IS-54B).  It is not
available to the public and is incredibly weak.

Finally, some of the implications behind this announcements are dire.  The
Wiretap chip could become the market or legislative standard.  This could
mean that other implementations of cryptographic voice transactions would
be very difficult to obtain or would be illegal to obtain.  Why would a
criminal use the Wiretap chip when they knew it wouldn't encrypt their
conversations against the LE agencies?  They wouldn't, they would use other
encryption technologies.  Would this mean that using something other than
the Wiretap chip is probable cause and puts you under suspicion?  The way
the encryption works also allows for ludicrously easy call-tracing.  Each
chip has a serial number that is transmitted with each message.  That
serial number is encrypted with the "Family" key.  This key is the *same*
for every chip.  You gain that key and you can track when and for how long
any person or groups of people calls *anyone* else.  (Easy to do, since any
LE agency can gain the 'family' key with a search warrant.  It would leak
easily into other hands.)

One last fishy thing is that AT&T has already (on the same day) announced
phones with this chip.  This implies (means?) that AT&T has known about
this chip for a while.  They seem to be more concerned about getting a jump
on the competition than producing a product that will actually give their
users real security.  'Course, there is the question of collusion between
the governement and industry.  Only two companies will be allowed to
manufacture the chip, VLSI and Mykotronix.  Jeff Hendy, director of new
product marketing for VLSI, says his company expects to make $50 million of
the chip in the next 3 years.  (This from the San Jose Mercury News.)

Permission is granted to distribute this document to whomsoever you should
desire.  You may change it only if you send me the changes.

Think Free,
--
Defeat the        Torin/Darren Stalder/Wolf           __
  Wiretap Chip    Internet:  dstalder@gmuvax2.gmu.edu \/ PGP2.x key available.
  Proposal!       Bitnet:    dstalder@gmuvax                  Finger me.
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