From: karn@servo.qualcomm.com (Phil Karn)
Subject: Re: the Right of Privacy (was Re: A Trial Balloon to Ban 
Organization: Qualcomm, Inc
Date: Thu, 29 Oct 1992 08:05:33 GMT


I sent the following note to RISKS the other day:

--Phil
----------

David Willcox spoke of the obvious risks of registering encryption
keys with some agency. Dorothy Denning responded in RISKS 13.86 that
the "risk can be reduced to about zero" and described a mechanism. Yet
neither elaborated on just what specific risks are to be protected
against.

Denning chooses to ignore one obvious class of risks: defective
warrants, incompetence and/or outright corruption in the government
and the key registration agency. The government has abused its wiretap
facilities in the past (e.g., Operation Shamrock) and will do so again
until the widespread use of strong cryptography stops it.

Anyone who thinks that the warrant is a meaningful safeguard ought to
consider what happened recently in Poway, California (just northeast
of San Diego). Customs and DEA agents broke into an innocent man's
house at midnight and exchanged gunfire with the owner, who quite
reasonably thought his home was being invaded (the agents did not
identify themselves). Last I heard, the owner was in critical
condition in the hospital. After the shooting, neighbors overheard the
leader telling his troops "Now get this straight. He shot first!"

The sole basis of the warrant? A "tip" from an informer, already known
by Customs to be unreliable. He admitted the next day that he had
merely picked a house at random when the agents pressed him to
"produce".

The judge who approved this particular warrant obviously didn't
scrutinize it very closely despite the clear potential for serious
injury to an innocent person. It's not hard to imagine a judge being
even less critical of an application for a wiretap warrant. "After
all", he'll reason, "what harm can to you really do to an innocent
person by just listening to his phone calls?  It's not like the agents
are asking for permission to break his door down."

That's the whole problem with government wiretaps. They're easy and
(from law enforcement's perspective) almost risk-free. Break down the
wrong guy's door, and there's no way to keep it out of the papers.
But tap the wrong guy's phone and he may never know. Warrants?  Don't
bother -- they leave paper trails, and are unnecessary unless you want
to produce the recordings in court. There are many other uses for
wiretaps that need not reveal one's "sources and methods".

This is especially tempting with radio. ECPA or no ECPA, the fact is
that it's incredibly easy to intercept analog cell phones and very
hard to get caught doing it.  Indeed, the government successfully
opposed meaningful encryption in digital cellular, even though it
would only protect the air link -- the land side of the call could
still be tapped with the phone company's assistance.  I wonder why.

Okay, so maybe I'm paranoid. But I don't think so. A healthy distrust
of government, particularly of those functions that are not always
open to public scrutiny, is essential to a free society. Or so the
authors of the Constitution seemed to think, even if the average
person wouldn't mind repealing the Bill of Rights to help fight the
drug war.

But let's assume that we've found some saints to populate the entire
Executive branch, so we can safely pass a law requiring crypto key
registration. Exactly how would it be enforced? Routinely scan all
private telephone conversations looking for bit streams that cannot be
easily decoded? What about certain rare natural languages - ban them
too? (Recall that the US military used Navajo radio operators in the
Pacific during WWII as "human crypto machines" against the Japanese).
So much for the First Amendment.

Suppose you find an undecodable conversation that you actually have
good reason to believe conceals criminal activity. How would you
compel the users to reveal the key, if indeed they used a protocol
that could be compromised in this way? According to several lawyers
I've asked, including a law professor at the University of Wisconsin
who specializes in the Fifth Amendment, a memorized crypto key would
clearly be considered "testimonial" evidence that could not be
compelled without a grant of immunity. So what do we do -- repeal the
Fifth Amendment too?

It is absolutely obvious to me that any attempt to control the private
use of cryptography could not help but impinge on some very basic
Constitutional guarantees. And yet it probably still wouldn't have the
desired effect. It's already a cliche, but it's still true: when
cryptography is outlawed, only outlaws will use cryptography. (And no,
I *don't* believe the same is true for guns.)

Phil