This article only hints at what was well known at the time-- that this was simply the first step in an attempt to outlaw cryptography altogether.<p>The next step was to either pass a law requiring key disclosure, our outlaw cryptography alltoegether. If you think that sounds far fetched... remember at the time this article was written they were trying to jail Phill Zimmerman for writing PGP.
Operation of Clipper: <a href="http://www.crypto.com/papers/escrow-acsac11.pdf" rel="nofollow">http://www.crypto.com/papers/escrow-acsac11.pdf</a><p>"Clipper was intended as a drop-
in replacement for a standard DES chip, but with a new
symmetric-key cipher algorithm, called
Skipjack
, designed
by the National Security Agency and using an 80 bit key.
But before any two Clipper chips could communicate, they
would first exchange a
Law Enforcement Access Field (LEAF)
that contained a copy of the current session key, itself en-
crypted with an “escrowed”
Unit Key
held by the govern-
ment. Any Clipper-encrypted communication could thus be
decrypted by government agents without needing to break
the (presumably strong) Skipjack cipher. The agents would
be able to recover the session key simply by decrypting the
copy in the LEAF (which they would intercept along with
the ciphertext) using their escrowed copy of the unit key"<p>It had a fatal flaw: a 16-bit checksum that could be brute-forced.
Thought it was interesting that plans for the Clipper Chip were canceled around the time the recently discovered CPU vulnerabilities were introduced. Extremely unlikely that there was some conspiracy given the number of vendors affected, but a possibility given the magnitude of the military budget and the value of being able to decrypt enemy communications via side-channel attacks.
The documentary “The Century of the Self” has a section on the Clipper chip. It showed video of a Clinton campaign manager explaining to volunteers that “Yeah, we know this is stupid, but it’s an important part of our message that we are here to protect your children.”<p>The documentary is excellent all around. Highly recommended. Possibly available on YouTube.