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David Golombek, daveg@mit.edu\\
6.805 Paper \#3: The Encryption Debate

Within a month of each other, Ronald Rivest of the MIT Laboratory for
Computer Science and Louis Freeh, director of the FBI, both presented
their views on encryption to the Senate Judiciary Committee on
Encryption.  Louis Freeh was able to present his arguments in person,
while Rivest was only able to submit his via mail, but Rivest's letter
of June 10, 1997 and Freeh's presentation on July 9, 1997 are very
interesting to examine together for the very differing views they
provide on encryption debate.  This paper will examine these two
documents for the arguments each presents and attempt to discern the
motivations behind those arguments.

Rivest begins by his arguments by defining authentication and
confidentiality and giving examples of their use of in everyday life.
He states that they are vital to the infrastructure of all computer
networks, an inseparable part of all computer communications, and that
cryptography is the best (and only) known method of achieving these
goals.  He presents all of this as a statement of fact, not open to
argument.  Cryptography is simply a tool, an egalitarian technology
that anyone can use, and it is the motivation of the user that makes
it good or bad, not anything inherent in the technology itself.
However, now that more of our communications are taking place over
electronic medium, privacy in conversation is becoming more scarce.
Previously, a face to face conversation was normal, and highly secure;
now, electronic communications are the norm, and privacy has suffered.
The current state of privacy for electronic communications is
unacceptable --- evesdropping and falsification are simple matters,
both in attacks versus individuals and corporations.  The law
enforcement community has grown used to this state of affairs, and
uses this weakness to use wiretapping in its criminal investigations.
However, cryptography is quickly becoming more universal as secure
communications become more important to commerce.  This growth of
cryptography is good for law enforcement because it will stop a type
of crime that is quickly on the rise, namely information theft and
fraud.  It is also good for national security, preventing terrorists
from attacking our vital infrastructures.  Cryptography is a defensive
technology, one that protects its users from harm and does no harm on
its own.

This is the uncontroversial section of Rivest's argument --- Freeh
concedes all of this as true very quickly in his presentation.  The
important point of this section of Rivest's paper is the light in
which he presents cryptography --- it a technology coming to save us,
one that is badly needed.  Rather than something we should be wary of,
we should embrace cryptography whole-heartedly.  Freeh on the other
hands from the beginning approaches cryptography as something we need
to be careful of.  He agrees that is is badly needed, but focuses on
it's uses by ``drug lords, spies, terrorists, and even violent gangs''
rather than by normal citizens.  Freeh also mentions a point that
Rivest skips, that most companies want some sort of key recovery
internally, in order not to lose data vital to the company if the
person knowing the pass phrase dies or leaves the company.  Thus,
Freeh presents key recovery as being the savior of cryptography,
being the key part of the technology that tranforms it from good to
bad.  

Rivest continues on, beginning to present the arguments he expects his
oponents to use, in order to present counter-arguments.  He strikes to
the heart of the matter immediately, stating the worry of many that
``bad guys'' will use cryptography, preventing the ``good guys'' from
tapping their communications.  Rivest counters that this is the case
with all technologies; anyone can use them, and it is always worrisome
when the bad guys gain advantage from them.  However, this does not
mean all technologies should be heavily regulated.  A technology must
both be able to be regulated, and the benefits of doing so should
outweigh the costs and disadvantages.  

Freeh too moves onto this matter of bad guys using cryptography
quickly.  He attempts to show that wiretapping is suddenly one of the
most important tools available to law enforcement agencies, vital in
cracking and prosecuting such cases as a plan to bomb various New York
locations, and in a foiled plot to kidnap, molest, and kill an young
child.  He also gives examples of crimes in which cryptography was
used, and claims these instances are quickly on the rise.

This section is the core of Freeh's presentation --- he is attempting
to scare the committee into regulating cryptography.  He is stating a
few cases, highlighting just a couple, and essentially saying that if
strong cryptography were available without key recovery were in use,
the crimes would have been pulled off successfully.  His case is
weakened by the scarcity of cases he is able to cite, and his lack of
proof that the crimes would not otherwise have been stopped.  Freeh is
using his credibility as director of the FBI to assure the committee
that law enforcement will really be crippled if key recovery is not
availability, seeming to ignore how infrequently, statistically,
wiretapping is actually used in investigations.

Rivst continues on, saying that cryptography cannot be easily
regulated for two reasons.  First, if we weaken the cryptosystems that
anyone can use, we open the good guys up to attacks that cryptography
was supposed to prevent.  Key recovery weakens the mathematical
backing of the cryptography system itself, and opens up many new
avenues of social attacks, from stealing of legitimately obtained
keys, to the corruption of the administers of the keys to obtain keys
directly. Second, cryptography is hard to regulate because it is easy
to reproduce, but without having the key recovery features built in.
Descriptions (including source code) of very strong cryptography are
easily available all over the world, and it is naive to believe
everyone will use key-recoverable cryptography when others are
available (regardless of any laws passed).

This is perhaps the most controversial section of Rivest's document,
with its alarmist description of the national information
infrastructure ``dissapearing in the flames of keys 'recovered' by
organized crime.''  He is directly attacking the government, claiming
it is incapable of properly administering the key database.  This
argument is designed to appeal to those skeptical of government; with
this system, we'd be placing a lot of responsibility in the
government, a weakness that is simply not needed.  Rivest also attacks
the mathematical foundations of key recovery, a claim he is uniquely
able to make, being one of the writers of a paper describing the risks
of providing key recovery.  His argument that we shouldn't regulate
cryptography because it is trivial to reproduce is one of the weaker
points of the document, poorly phrased and weakly supported.  It seems
to be added in at the last minute, something Rivest sees as obvious,
but doesn't do a good job of backing up.

Rivest finishes up by claiming that the disadvantages of regulating
cryptography are are greater than the advantages brought by those
regulations.  He compares cryptography to duct tape --- both are
extremely useful, integral to our every day lives, and useful all over
the place.  We wouldn't want to live without the advantages of
duct tape --- we shouldn't want to live without the advantages of
cryptography.  Meanwhile, Freeh finishes off by saying that
cryptography is indeed needed, but that by adding key recovery (which
he claims has no weaknesses), we can make it the good for everybody,
both helping the good guys and allowing the continued fight against
the bad guys.

It is this claim of Rivest's that key recovery has potential
weaknesses that separates the two presentations so drastically.  Both
people say that cryptography is crucial the good guys, and that it is
bad if the bad guys use it to avoid detection and prosecution.  Freeh
claims key recovery allows a harmless way of avoiding the problem of
the bad guys, while Rivest claims that key recovery introduces to
great a weakness in the system, ruining it for the good guys, and
saying that the bad guys would probably not use the key recovery
system anyways.

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