Testimony of Philip R. Zimmermann to
the Subcommittee on Science, Technology, and Space
of the US Senate Committee on Commerce, Science, and
Transportation
26 June 1996
Mr. Chairman and members of the committee, my name is Philip
Zimmermann, and I'm Chairman and Chief Technology Officer for PGP
Inc, a newly-formed company that provides cryptographic products.
I'm here to talk to you today about S.1726 and the need to change
US export control policy for cryptographic software. I want to
thank you for the opportunity to be here to speak in favor of this
bill.
I'm the creator of PGP (Pretty Good Privacy), a public-key
encryption software package for the protection of electronic mail.
Since PGP was published domestically as freeware in June of 1991,
it has spread organically all over the world, and has since become
the de facto worldwide standard for encryption of E-mail, winning
numerous industry awards along the way. For three years I was the
target of a criminal investigation by the US Customs Service, who
assumed that laws were broken when PGP spread outside the US.
That investigation was closed without indictment in January 1996.
Computers were developed in secret back in World War II mainly to
break codes. Ordinary people did not have access to computers,
because they were few in number and too expensive. Some people
postulated that there would never be a need for more than half a
dozen computers in the country, and assumed that ordinary people
would never have a need for computers. Some of the government's
attitude toward cryptography today were formed in that period, and
mirrors the old attitudes toward computers. Why would ordinary
people need to have access to good cryptography?
In addition to the limited availability of computers, another
problem with cryptography in those days was that cryptographic
keys had to be distributed over secure channels so that both
parties could send encrypted traffic over insecure channels.
Governments solved that problem by dispatching key couriers with
satchels handcuffed to their wrists. Governments could afford to
send guys like these to their embassies overseas. But the great
masses of ordinary people would never have access to practical
cryptography if keys had to be distributed this way. No matter
how cheap and powerful personal computers might someday become,
you just can't send the keys electronically without the risk of
interception. This widened the feasibility gap between government
and personal access to cryptography.
Today, we live in a new world that has had two major breakthroughs
that have an impact on this state of affairs. The first is the
coming of the personal computer and the information age. The
second breakthrough is public-key cryptography.
With the first breakthrough comes cheap ubiquitous personal
computers, modems, FAX machines, the Internet, E-mail, the World-
Wide Web, digital cellular phones, personal digital assistants
(PDAs), wireless digital networks, ISDN, cable TV, and the data
superhighway. This information revolution is catalyzing the
emergence of a global economy.
But this renaissance in electronic digital communication brings
with it a disturbing erosion of our privacy. In the past, if the
government wanted to violate the privacy of ordinary citizens, it
had to expend a certain amount of effort to intercept and steam
open and read paper mail, and listen to and possibly transcribe
spoken telephone conversation. This is analogous to catching fish
with a hook and a line, one fish at a time. Fortunately for
freedom and democracy, this kind of labor-intensive monitoring is
not practical on a large scale.
Today, electronic mail is gradually replacing conventional paper
mail, and is soon to be the norm for everyone, not the novelty it
is today. Unlike paper mail, E-mail messages are just too easy to
intercept and scan for interesting keywords. This can be done
easily, routinely, automatically, and undetectably on a grand
scale. This is analogous to driftnet fishing-- making a
quantitative and qualitative Orwellian difference to the health of
democracy.
The second breakthrough came in the late 1970s, with the
mathematics of public key cryptography. This allows people to
communicate securely and conveniently with people they've never
met, with no prior exchange of keys over secure channels. No more
special key couriers with black bags. This, coupled with the
trappings of the information age, means the great masses of people
can at last use cryptography. This new technology also provides
digital signatures to authenticate transactions and messages, and
allows for digital money, with all the implications that has for
an electronic digital economy. (See appendix)
This convergence of technology-- cheap ubiquitous PCs, modems,
FAX, digital phones, information superhighways, et cetera-- is all
part of the information revolution. Encryption is just simple
arithmetic to all this digital hardware. All these devices will
be using encryption. The rest of the world uses it, and they
laugh at the US because we are railing against nature, trying to
stop it. Trying to stop this is like trying to legislate the
tides and the weather. It's like the buggy whip manufacturers
trying to stop the cars-- even with the NSA and the FBI on their
side, it's still impossible. The information revolution is good
for democracy-- good for a free market and trade. It contributed
to the fall of the Soviet empire. They couldn't stop it either.
Today, every off-the-shelf multimedia PC can become a secure voice
telephone, through the use of freely available software such as
PGPfone. When you combine that with the strong political will
that exists in the American people to have their privacy, it's
going to require extreme measures to control this technology.
What does this mean for the government's Clipper chip and key
escrow systems?
Like every new technology, this comes at some cost. Cars pollute
the air and cause traffic jams. Cryptography can help criminals
hide their activities. People in the law enforcement and
intelligence communities are going to look at this only in their
own terms. But even with these costs, we still can't stop this
from happening in a free market global economy. Most people I
talk to outside of government feel that the net result of
providing privacy will be positive.
Law enforcement and intelligence interests in the government have
attempted many times to suppress the availability of strong
domestic encryption technology.
In 1991, Senate Bill 266 included a non-binding resolution, which
if it had become real law, would have forced manufacturers of
secure communications equipment to insert special "trap doors" in
their products, so that the government could read anyone's
encrypted messages. Before that measure was defeated, I wrote and
released Pretty Good Privacy. I did it because I wanted
cryptography to be made available to the American public before it
became illegal to use it. I gave it away for free so that it
would achieve wide dispersal, to inoculate the body politic.
The 1994 Digital Telephony bill mandated that phone companies
install remote wiretapping ports into their central office digital
switches, creating a new technology infrastructure for "point-and-
click" wiretapping, so that federal agents no longer have to go
out and attach alligator clips to phone lines. Now they'll be
able to sit in their headquarters in Washington and listen in to
your phone calls. Of course, the law still requires a court order
for a wiretap. But while technology infrastructures tend to
persist for generations, laws and policies can change overnight.
Once a communications infrastructure optimized for surveillance
becomes entrenched, a shift in political conditions may lead to
abuse of this new-found power. Political conditions may shift
with the election of a new government, or perhaps more abruptly
from the bombing of a Federal building.
A year after the 1994 Digital Telephony bill passed, the FBI
disclosed plans to require the phone companies to build into their
infrastructure the capacity to simultaneously wiretap one percent
of all phone calls in all major US cities. This would represent
more than a thousandfold increase over previous levels in the
number of phones that could be wiretapped. In previous years,
there were only about 1000 court-ordered wiretaps in the US per
year, at the federal, state, and local levels combined. It's hard
to see how the government could even employ enough judges to sign
enough wiretap orders to wiretap 1% of all our phone calls, much
less hire enough federal agents to sit and listen to all that
traffic in real time. The only plausible way of processing that
amount of traffic is a massive Orwellian application of automated
voice recognition technology to sift through it all, searching for
interesting keywords or searching for a particular speaker's
voice. If the government doesn't find the target in the first 1%
sample, the wiretaps can be shifted over to a different 1% until
the target is found, or until everyone's phone line has been
checked for subversive traffic. The FBI says they need this
capacity to plan for the future. This plan sparked such outrage
that it was defeated in Congress, at least this time around, in
1995. But the mere fact that the FBI even asked for these broad
powers is revealing of their agenda. And the defeat of this plan
isn't so reassuring when you consider that the 1994 Digital
Telephony bill was also defeated the first time it was introduced,
in 1993.
Advances in technology will not permit the maintenance of the
status quo, as far as privacy is concerned. The status quo is
unstable. If we do nothing, new technologies will give the
government new automatic surveillance capabilities that Stalin
could never have dreamed of. The only way to hold the line on
privacy in the information age is strong cryptography.
Cryptography strong enough to keep out major governments.
The government has a track record that does not inspire confidence
that they will never abuse our civil liberties. The FBI's
COINTELPRO program targeted groups that opposed government
policies. They spied on the anti-war movement and the civil
rights movement. They wiretapped Martin Luther King's phone.
Nixon had his enemies list. And then there was the Watergate
mess. The War on Drugs has given America the world's largest per-
capita incarceration rate in the world, a distinction formerly
held by South Africa, before we surpassed them during the eighties
even when apartheid was in full swing. Recently, we've seen the
images and sounds of the Rodney King beatings, Detective Mark
Fuhrman's tapes boasting of police abuses, and the disturbing
events of the Ruby Ridge case. And now Congress and the Clinton
administration seem intent on passing laws curtailing our civil
liberties on the Internet. At no time in the past century has
public distrust of the government been so broadly distributed
across the political spectrum, as it is today.
The Clinton Administration seems to be attempting to deploy and
entrench a communications infrastructure that would deny the
citizenry the ability to protect its privacy. This is unsettling
because in a democracy, it is possible for bad people to
occasionally get elected-- sometimes very bad people. Normally, a
well-functioning democracy has ways to remove these people from
power. But the wrong technology infrastructure could allow such a
future government to watch every move anyone makes to oppose it.
It could very well be the last government we ever elect.
When making public policy decisions about new technologies for the
government, I think one should ask oneself which technologies
would best strengthen the hand of a police state. Then, do not
allow the government to deploy those technologies. This is simply
a matter of good civic hygiene.
In addition to the human rights arguments, there are technological
reasons why the current export control regime makes no sense
anymore.
There has been considerable debate about allowing the export of
implementations of the full 56-bit Data Encryption Standard (DES).
At an academic cryptography conference in 1993, Michael Wiener of
Northern Telecom in Ottawa presented a paper on how to crack the
DES with a special machine. He has fully designed and tested a
chip that guesses DES keys at high speed until it finds the right
one. Although he has refrained from building the real chips so
far, he can get these chips manufactured for $10.50 each, and can
build 57000 of them into a special machine for $1 million that can
try every DES key in 7 hours, averaging a solution in 3.5 hours.
$1 million can be hidden in the budget of many companies. For $10
million, it takes 21 minutes to crack, and for $100 million, just
two minutes. That's full 56-bit DES, cracked in just two minutes.
I'm sure the NSA can do it in seconds, with their budget. This
means that DES is now effectively dead for purposes of serious
data security applications. If Congress acts now to enable the
export of full DES products, it will be a day late and a dollar
short.
Knowledge of cryptography is becoming so widespread, that export
controls are no longer effective at controlling the spread of this
technology. People everywhere can and do write good cryptographic
software, and we import it here but cannot export it, to the
detriment of our indigenous software industry.
I wrote PGP from information in the open literature, putting it
into a convenient package that everyone can use in a desktop or
palmtop computer. Then I gave it away for free, for the good of
democracy. This could have popped up anywhere, and spread. Other
people could have and would have done it. And are doing it.
Again and again. All over the planet. This technology belongs to
everybody.
PGP has spread like a prairie fire, fanned by countless people who
fervently want their privacy restored in the information age.
Today, human rights organizations are using PGP to protect their
people overseas. Amnesty International uses it. The human rights
group in the American Association for the Advancement of Science
uses it. It is used to protect witnesses who report human rights
abuses in the Balkans, in Burma, in Guatemala, in Tibet.
Some Americans don't understand why I should be this concerned
about the power of government. But talking to people in Eastern
Europe, you don't have to explain it to them. They already get
it-- and they don't understand why we don't.
I want to read you a quote from some E-mail I got in October 1993
from someone in Latvia, on the day that Boris Yeltsin was shelling
his Parliament building:
"Phil I wish you to know: let it never be, but if
dictatorship takes over Russia your PGP is widespread from Baltic
to Far East now and will help democratic people if necessary.
Thanks."
Appendix -- How Public-Key Cryptography Works
In conventional cryptosystems, such as the US Federal Data
Encryption Standard (DES), a single key is used for both
encryption and decryption. This means that a key must be
initially transmitted via secure channels so that both parties
have it before encrypted messages can be sent over insecure
channels. This may be inconvenient. If you have a secure channel
for exchanging keys, then why do you need cryptography in the
first place?
In public key cryptosystems, everyone has two related
complementary keys, a publicly revealed key and a secret key.
Each key unlocks the code that the other key makes. Knowing the
public key does not help you deduce the corresponding secret key.
The public key can be published and widely disseminated across a
communications network. This protocol provides privacy without the
need for the same kind of secure channels that a conventional
cryptosystem requires.
Anyone can use a recipient's public key to encrypt a message to
that person, and that recipient uses her own corresponding secret
key to decrypt that message. No one but the recipient can decrypt
it, because no one else has access to that secret key. Not even
the person who encrypted the message can decrypt it.
Message authentication is also provided. The sender's own secret
key can be used to encrypt a message, thereby "signing" it. This
creates a digital signature of a message, which the recipient (or
anyone else) can check by using the sender's public key to decrypt
it. This proves that the sender was the true originator of the
message, and that the message has not been subsequently altered by
anyone else, because the sender alone possesses the secret key
that made that signature. Forgery of a signed message is
infeasible, and the sender cannot later disavow his signature.
These two processes can be combined to provide both privacy and
authentication by first signing a message with your own secret
key, then encrypting the signed message with the recipient's
public key. The recipient reverses these steps by first decrypting
the message with her own secret key, then checking the enclosed
signature with your public key. These steps are done
automatically by the recipient's software.
Philip Zimmermann
3021 11th Street
Boulder, Colorado 80304
303 541-0140
E-mail: prz(a)pgp.com
