From: Bruce Schneier [mailto:[log in to unmask]] Sent: Monday, October 01, 2001 2:11 AM
To: [log in to unmask]
Subject: CRYPTO-GRAM SPECIAL ISSUE, September 30, 2001
CRYPTO-GRAM
September 30, 2001
by Bruce Schneier
Founder and CTO
Counterpane Internet Security, Inc.
[log in to unmask]
<http://www.counterpane.com>
A free monthly newsletter providing summaries, analyses, insights, and
commentaries on computer and network security.
Back issues are available at
<http://www.counterpane.com/crypto-gram.html>. To subscribe, visit
<http://www.counterpane.com/crypto-gram.html> or send a blank message to
[log in to unmask]
Copyright (c) 2001 by Counterpane Internet Security, Inc.
** *** ***** ******* *********** *************
This is a special issue of Crypto-Gram, devoted to the September 11
terrorist attacks and their aftermath.
Please distribute this issue widely.
In this issue:
The Attacks
Airline Security Regulations
Biometrics in Airports
Diagnosing Intelligence Failures
Regulating Cryptography
Terrorists and Steganography
News
Protecting Privacy and Liberty
How to Help
** *** ***** ******* *********** *************
The Attacks
Watching the television on September 11, my primary reaction was amazement.
The attacks were amazing in their diabolicalness and audacity: to hijack
fuel-laden commercial airliners and fly them into buildings, killing
thousands of innocent civilians. We'll probably never know if the
attackers realized that the heat from the jet fuel would melt the steel
supports and collapse the World Trade Center. It seems probable that they
placed advantageous trades on the world's stock markets just before the
attack. No one planned for an attack like this. We like to think that
human beings don't make plans like this.
I was impressed when al-Qaeda simultaneously bombed two American embassies
in Africa. I was more impressed when they blew a 40-foot hole in an
American warship. This attack makes those look like minor operations.
The attacks were amazing in their complexity. Estimates are that the plan
required about 50 people, at least 19 of them willing to die. It required
training. It required logistical support. It required coordination. The
sheer scope of the attack seems beyond the capability of a terrorist
organization.
The attacks rewrote the hijacking rule book. Responses to hijackings are
built around this premise: get the plane on the ground so negotiations can
begin. That's obsolete now.
They rewrote the terrorism book, too. Al-Qaeda invented a new type of
attacker. Historically, suicide bombers are young, single, fanatical, and
have nothing to lose. These people were older and more experienced. They
had marketable job skills. They lived in the U.S.: watched television, ate
fast food, drank in bars. One left a wife and four children.
It was also a new type of attack. One of the most difficult things about a
terrorist operation is getting away. This attack neatly solved that
problem. It also solved the technological problem. The United States
spends billions of dollars on remote-controlled precision-guided munitions;
al-Qaeda just finds morons willing to fly planes into skyscrapers.
Finally, the attacks were amazing in their success. They weren't
perfect. We know that 100% of the attempted hijackings were successful,
and 75% of the hijacked planes successfully hit their targets. We don't
know how many planned hijackings were aborted for one reason or
another. What's most amazing is that the plan wasn't leaked. No one
successfully defected. No one slipped up and gave the plan away. Al-Qaeda
had assets in the U.S. for months, and managed to keep the plan
secret. Often law enforcement has been lucky here; in this case we weren't.
Rarely do you see an attack that changes the world's conception of attack,
as these terrorist attacks changed the world's conception of what a
terrorist attack can do. Nothing they did was novel, yet the attack was
completely new. And our conception of defense must change as well.
** *** ***** ******* *********** *************
Airline Security Regulations
Computer security experts have a lot of expertise that can be applied to
the real world. First and foremost, we have well-developed senses of what
security looks like. We can tell the difference between real security and
snake oil. And the new airport security rules, put in place after
September 11, look and smell a whole lot like snake oil.
All the warning signs are there: new and unproven security measures, no
real threat analysis, unsubstantiated security claims. The ban on cutting
instruments is a perfect example. It's a knee-jerk reaction: the
terrorists used small knives and box cutters, so we must ban them. And
nail clippers, nail files, cigarette lighters, scissors (even small ones),
tweezers, etc. But why isn't anyone asking the real questions: what is the
threat, and how does turning an airplane into a kindergarten classroom
reduce the threat? If the threat is hijacking, then the countermeasure
doesn't protect against all the myriad of ways people can subdue the pilot
and crew. Hasn't anyone heard of karate? Or broken bottles? Think about
hiding small blades inside luggage. Or composite knives that don't show up
on metal detectors.
Parked cars now must be 300 feet from airport gates. Why? What security
problem does this solve? Why doesn't the same problem imply that passenger
drop-off and pick-up should also be that far away? Curbside check-in has
been eliminated. What's the threat that this security measure has
solved? Why, if the new threat is hijacking, are we suddenly worried about
bombs?
The rule limiting concourse access to ticketed passengers is another one
that confuses me. What exactly is the threat here? Hijackers have to be
on the planes they're trying to hijack to carry out their attack, so they
have to have tickets. And anyone can call Priceline.com and "name their
own price" for concourse access.
Increased inspections -- of luggage, airplanes, airports -- seem like a
good idea, although it's far from perfect. The biggest problem here is
that the inspectors are poorly paid and, for the most part, poorly educated
and trained. Other problems include the myriad ways to bypass the
checkpoints -- numerous studies have found all sorts of violations -- and
the impossibility of effectively inspecting everybody while maintaining the
required throughput. Unidentified armed guards on select flights is
another mildly effective idea: it's a small deterrent, because you never
know if one is on the flight you want to hijack.
Positive bag matching -- ensuring that a piece of luggage does not get
loaded on the plane unless its owner boards the plane -- is actually a good
security measure, but assumes that bombers have self-preservation as a
guiding force. It is completely useless against suicide bombers.
The worst security measure of them all is the photo ID requirement. This
solves no security problem I can think of. It doesn't even identify
people; any high school student can tell you how to get a fake ID. The
requirement for this invasive and ineffective security measure is secret;
the FAA won't send you the written regulations if you ask. Airlines are
actually more stringent about this than the FAA requires, because the
"security" measure solves a business problem for them.
The real point of photo ID requirements is to prevent people from reselling
tickets. Nonrefundable tickets used to be regularly advertised in the
newspaper classifieds. Ads would read something like "Round trip, Boston
to Chicago, 11/22 - 11/30, female, $50." Since the airlines didn't check
ID but could notice gender, any female could buy the ticket and fly the
route. Now this doesn't work. The airlines love this; they solved a
problem of theirs, and got to blame the solution on FAA security
requirements.
Airline security measures are primarily designed to give the appearance of
good security rather than the actuality. This makes sense, once you
realize that the airlines' goal isn't so much to make the planes hard to
hijack, as to make the passengers willing to fly. Of course airlines would
prefer it if all their flights were perfectly safe, but actual hijackings
and bombings are rare events and they know it.
This is not to say that all airport security is useless, and that we'd be
better off doing nothing. All security measures have benefits, and all
have costs: money, inconvenience, etc. I would like to see some rational
analysis of the costs and benefits, so we can get the most security for the
resources we have.
One basic snake-oil warning sign is the use of self-invented security
measures, instead of expert-analyzed and time-tested ones. The closest the
airlines have to experienced and expert analysis is El Al. Since 1948 they
have been operating in and out of the most heavily terroristic areas of the
planet, with phenomenal success. They implement some pretty heavy security
measures. One thing they do is have reinforced, locked doors between their
airplanes' cockpit and the passenger section. (Notice that this security
measure is 1) expensive, and 2) not immediately perceptible to the
passenger.) Another thing they do is place all cargo in decompression
chambers before takeoff, to trigger bombs set to sense altitude. (Again,
this is 1) expensive, and 2) imperceptible, so unattractive to American
airlines.) Some of the things El Al does are so intrusive as to be
unconstitutional in the U.S., but they let you take your pocketknife on
board with you.
Airline security:
<http://www.time.com/time/covers/1101010924/bsecurity.html>
<http://www.accessatlanta.com/ajc/terrorism/atlanta/0925gun.html>
FAA on new security rules:
<http://www.faa.gov/apa/faq/pr_faq.htm>
A report on the rules' effectiveness:
<http://www.boston.com/dailyglobe2/266/nation/Passengers_say_banned_items_ha
ve_eluded_airport_monitors+.shtml>
El Al's security measures:
<http://news.excite.com/news/ap/010912/18/israel-safe-aviation>
<http://news.excite.com/news/r/010914/07/international-attack-israel-elal-dc
>
More thoughts on this topic:
<http://slate.msn.com/HeyWait/01-09-17/HeyWait.asp>
<http://www.tnr.com/100101/easterbrook100101.html>
<http://www.tisc2001.com/newsletters/317.html>
Two secret FAA documents on photo ID requirement, in text and GIF:
<http://www.cs.berkeley.edu/~daw/faa/guid/guid.txt>
<http://www.cs.berkeley.edu/~daw/faa/guid/guid.html>
<http://www.cs.berkeley.edu/~daw/faa/id/id.txt>
<http://www.cs.berkeley.edu/~daw/faa/id/id.html>
Passenger profiling:
<http://www.latimes.com/news/nationworld/nation/la-091501profile.story>
A CATO Institute report: "The Cost of Antiterrorist Rhetoric," written well
before September 11:
<http://www.cato.org/pubs/regulation/reg19n4e.html>
I don't know if this is a good idea, but at least someone is thinking about
the problem:
<http://www.zdnet.com/anchordesk/stories/story/0,10738,2812283,00.html>
** *** ***** ******* *********** *************
Biometrics in Airports
You have to admit, it sounds like a good idea. Put cameras throughout
airports and other public congregation areas, and have automatic
face-recognition software continuously scan the crowd for suspected
terrorists. When the software finds one, it alerts the authorities, who
swoop down and arrest the bastards. Voila, we're safe once again.
Reality is a lot more complicated; it always is. Biometrics is an
effective authentication tool, and I've written about it before. There are
three basic kinds of authentication: something you know (password, PIN
code, secret handshake), something you have (door key, physical ticket into
a concert, signet ring), and something you are (biometrics). Good security
uses at least two different authentication types: an ATM card and a PIN
code, computer access using both a password and a fingerprint reader, a
security badge that includes a picture that a guard looks at. Implemented
properly, biometrics can be an effective part of an access control system.
I think it would be a great addition to airport security: identifying
airline and airport personnel such as pilots, maintenance workers,
etc. That's a problem biometrics can help solve. Using biometrics to pick
terrorists out of crowds is a different kettle of fish.
In the first case (employee identification), the biometric system has a
straightforward problem: does this biometric belong to the person it claims
to belong to? In the latter case (picking terrorists out of crowds), the
system needs to solve a much harder problem: does this biometric belong to
anyone in this large database of people? The difficulty of the latter
problem increases the complexity of the identification, and leads to
identification failures.
Setting up the system is different for the two applications. In the first
case, you can unambiguously know the reference biometric belongs to the
correct person. In the latter case, you need to continually worry about
the integrity of the biometric database. What happens if someone is
wrongfully included in the database? What kind of right of appeal does he
have?
Getting reference biometrics is different, too. In the first case, you can
initialize the system with a known, good biometric. If the biometric is
face recognition, you can take good pictures of new employees when they are
hired and enter them into the system. Terrorists are unlikely to pose for
photo shoots. You might have a grainy picture of a terrorist, taken five
years ago from 1000 yards away when he had a beard. Not nearly as useful.
But even if all these technical problems were magically solved, it's still
very difficult to make this kind of system work. The hardest problem is
the false alarms. To explain why, I'm going to have to digress into
statistics and explain the base rate fallacy.
Suppose this magically effective face-recognition software is 99.99 percent
accurate. That is, if someone is a terrorist, there is a 99.99 percent
chance that the software indicates "terrorist," and if someone is not a
terrorist, there is a 99.99 percent chance that the software indicates
"non-terrorist." Assume that one in ten million flyers, on average, is a
terrorist. Is the software any good?
No. The software will generate 1000 false alarms for every one real
terrorist. And every false alarm still means that all the security people
go through all of their security procedures. Because the population of
non-terrorists is so much larger than the number of terrorists, the test is
useless. This result is counterintuitive and surprising, but it is
correct. The false alarms in this kind of system render it mostly
useless. It's "The Boy Who Cried Wolf" increased 1000-fold.
I say mostly useless, because it would have some positive effect. Once in
a while, the system would correctly finger a frequent-flyer terrorist. But
it's a system that has enormous costs: money to install, manpower to run,
inconvenience to the millions of people incorrectly identified, successful
lawsuits by some of those people, and a continued erosion of our civil
liberties. And all the false alarms will inevitably lead those managing
the system to distrust its results, leading to sloppiness and potentially
costly mistakes. Ubiquitous harvesting of biometrics might sound like a
good idea, but I just don't think it's worth it.
Phil Agre on face-recognition biometrics:
<http://dlis.gseis.ucla.edu/people/pagre/bar-code.html>
My original essay on biometrics:
<http://www.counterpane.com/crypto-gram-9808.html#biometrics>
Face recognition useless in airports:
<http://www.theregister.co.uk/content/4/21916.html>
According to a DARPA study, to detect 90 per cent of terrorists we'd need
to raise an alarm for one in every three people passing through the airport.
A company that is pushing this idea:
<http://www.theregister.co.uk/content/6/21882.html>
A version of this article was published here:
<http://www.extremetech.com/article/0,3396,s%253D1024%2526a%253D15070,00.asp
>
** *** ***** ******* *********** *************
Diagnosing Intelligence Failures
It's clear that U.S. intelligence failed to provide adequate warning of the
September 11 terrorist attacks, and that the FBI failed to prevent the
attacks. It's also clear that there were all sorts of indications that the
attacks were going to happen, and that there were all sorts of things that
we could have noticed but didn't. Some have claimed that this was a
massive intelligence failure, and that we should have known about and
prevented the attacks. I am not convinced.
There's a world of difference between intelligence data and intelligence
information. In what I am sure is the mother of all investigations, the
CIA, NSA, and FBI have uncovered all sorts of data from their files, data
that clearly indicates that an attack was being planned. Maybe it even
clearly indicates the nature of the attack, or the date. I'm sure lots of
information is there, in files, intercepts, computer memory.
Armed with the clarity of hindsight, it's easy to look at all the data and
point to what's important and relevant. It's even easy to take all that
important and relevant data and turn it into information. And it's real
easy to take that information and construct a picture of what's going on.
It's a lot harder to do before the fact. Most data is irrelevant, and most
leads are false ones. How does anyone know which is the important one,
that effort should be spent on this specific threat and not the thousands
of others?
So much data is collected -- the NSA sucks up an almost unimaginable
quantity of electronic communications, the FBI gets innumerable leads and
tips, and our allies pass all sorts of information to us -- that we can't
possibly analyze it all. Imagine terrorists are hiding plans for attacks
in the text of books in a large university library; you have no idea how
many plans there are or where they are, and the library expands faster than
you can possibly read it. Deciding what to look at is an impossible task,
so a lot of good intelligence goes unlearned.
We also don't have any context to judge the intelligence effort. How many
terrorist attempts have been thwarted in the past year? How many groups
are being tracked? If the CIA, NSA, and FBI succeed, no one ever
knows. It's only in failure that they get any recognition.
And it was a failure. Over the past couple of decades, the U.S. has relied
more and more on high-tech electronic eavesdropping (SIGINT and COMINT) and
less and less on old fashioned human intelligence (HUMINT). This only
makes the analysis problem worse: too much data to look at, and not enough
real-world context. Look at the intelligence failures of the past few
years: failing to predict India's nuclear test, or the attack on the USS
Cole, or the bombing of the two American embassies in Africa; concentrating
on Wen Ho Lee to the exclusion of the real spies, like Robert Hanssen.
But whatever the reason, we failed to prevent this terrorist attack. In
the post mortem, I'm sure there will be changes in the way we collect and
(most importantly) analyze anti-terrorist data. But calling this a massive
intelligence failure is a disservice to those who are working to keep our
country secure.
Intelligence failure is an overreliance on eavesdropping and not enough on
human intelligence:
<http://www.sunspot.net/bal-te.intelligence13sep13.story>
<http://www.newscientist.com/news/news.jsp?id=ns99991297>
Another view:
<http://www.wired.com/news/politics/0,1283,46746,00.html>
Too much electronic eavesdropping only makes things harder:
<http://www.wired.com/news/business/0,1367,46817,00.html>
Israel alerted the U.S. about attacks:
<http://www.latimes.com/news/nationworld/nation/la-092001probe.story>
Mostly retracted:
<http://www.latimes.com/news/nationworld/nation/la-092101mossad.story>
** *** ***** ******* *********** *************
Regulating Cryptography
In the wake of the devastating attacks on New York's World Trade Center and
the Pentagon, Senator Judd Gregg and other high-ranking government
officials quickly seized on the opportunity to resurrect limits on strong
encryption and key escrow systems that ensure government access to
encrypted messages.
I think this is a bad move. It will do little to thwart terrorist
activities, while at the same time significantly reducing the security of
our own critical infrastructure. We've been through these arguments
before, but legislators seem to have short memories. Here's why trying to
limit cryptography is bad for Internet security.
One, you can't limit the spread of cryptography. Cryptography is
mathematics, and you can't ban mathematics. All you can ban is a set of
products that use that mathematics, but that is something quite
different. Years ago, during the cryptography debates, an international
crypto survey was completed; it listed almost a thousand products with
strong cryptography from over a hundred countries. You might be able to
control cryptography products in a handful of industrial countries, but
that won't prevent criminals from importing them. You'd have to ban them
in every country, and even then it won't be enough. Any terrorist
organization with a modicum of skill can write its own cryptography
software. And besides, what terrorist is going to pay attention to a legal
ban?
Two, any controls on the spread of cryptography hurt more than they
help. Cryptography is one of the best security tools we have to protect
our electronic world from harm: eavesdropping, unauthorized access,
meddling, denial of service. Sure, by controlling the spread of
cryptography you might be able to prevent some terrorist groups from using
cryptography, but you'll also prevent bankers, hospitals, and air-traffic
controllers from using it. (And, remember, the terrorists can always get
the stuff elsewhere: see my first point.) We've got a lot of electronic
infrastructure to protect, and we need all the cryptography we can get our
hands on. If anything, we need to make strong cryptography more prevalent
if companies continue to put our planet's critical infrastructure online.
Three, key escrow doesn't work. Short refresher: this is the notion that
companies should be forced to implement back doors in crypto products such
that law enforcement, and only law enforcement, can peek in and eavesdrop
on encrypted messages. Terrorists and criminals won't use it. (Again, see
my first point.)
Key escrow also makes it harder for the good guys to secure the important
stuff. All key-escrow systems require the existence of a highly sensitive
and highly available secret key or collection of keys that must be
maintained in a secure manner over an extended time period. These systems
must make decryption information quickly accessible to law enforcement
agencies without notice to the key owners. Does anyone really think that
we can build this kind of system securely? It would be a security
engineering task of unbelievable magnitude, and I don't think we have a
prayer of getting it right. We can't build a secure operating system, let
alone a secure computer and secure network.
Stockpiling keys in one place is a huge risk just waiting for attack or
abuse. Whose digital security do you trust absolutely and without
question, to protect every major secret of the nation? Which operating
system would you use? Which firewall? Which applications? As attractive
as it may sound, building a workable key-escrow system is beyond the
current capabilities of computer engineering.
Years ago, a group of colleagues and I wrote a paper outlining why key
escrow is a bad idea. The arguments in the paper still stand, and I urge
everyone to read it. It's not a particularly technical paper, but it lays
out all the problems with building a secure, effective, scalable key-escrow
infrastructure.
The events of September 11 have convinced a lot of people that we live in
dangerous times, and that we need more security than ever before. They're
right; security has been dangerously lax in many areas of our society,
including cyberspace. As more and more of our nation's critical
infrastructure goes digital, we need to recognize cryptography as part of
the solution and not as part of the problem.
My old "Risks of Key Recovery" paper:
<http://www.counterpane.com/key-escrow.html>
Articles on this topic:
<http://cgi.zdnet.com/slink?140437:8469234>
<http://www.wired.com/news/politics/0,1283,46816,00.html>
<http://www.pcworld.com/news/article/0,aid,62267,00.asp>
<http://www.newscientist.com/news/news.jsp?id=ns99991309>
<http://www.zdnet.com/zdnn/stories/news/0,4586,2814833,00.html>
Al-Qaeda did not use encryption to plan these attacks:
<http://dailynews.yahoo.com/h/nm/20010918/ts/attack_investigation_dc_23.html
>
Poll indicates that 72 percent of Americans believe that anti-encryption
laws would be "somewhat" or "very" helpful in preventing a repeat of last
week's terrorist attacks on New York's World Trade Center and the Pentagon
in Washington, D.C. No indication of what percentage actually understood
the question.
<http://news.cnet.com/news/0-1005-200-7215723.html?tag=mn_hd>
** *** ***** ******* *********** *************
Terrorists and Steganography
Guess what? Al-Qaeda may use steganography. According to nameless "U.S.
officials and experts" and "U.S. and foreign officials," terrorist groups
are "hiding maps and photographs of terrorist targets and posting
instructions for terrorist activities on sports chat rooms, pornographic
bulletin boards and other Web sites."
I've written about steganography in the past, and I don't want to spend
much time retracing old ground. Simply, steganography is the science of
hiding messages in messages. Typically, a message (either plaintext or,
more cleverly, ciphertext) is encoded as tiny changes to the color of the
pixels of a digital photograph. Or in imperceptible noise in an audio
file. To the uninitiated observer, it's just a picture. But to the sender
and receiver, there's a message hiding in there.
It doesn't surprise me that terrorists are using this trick. The very
aspects of steganography that make it unsuitable for normal corporate use
make it ideally suited for terrorist use. Most importantly, it can be used
in an electronic dead drop.
If you read the FBI affidavit against Robert Hanssen, you learn how Hanssen
communicated with his Russian handlers. They never met, but would leave
messages, money, and documents for one another in plastic bags under a
bridge. Hanssen's handler would leave a signal in a public place -- a
chalk mark on a mailbox -- to indicate a waiting package. Hanssen would
later collect the package.
That's a dead drop. It has many advantages over a face-to-face
meeting. One, the two parties are never seen together. Two, the two
parties don't have to coordinate a rendezvous. Three, and most
importantly, one party doesn't even have to know who the other one is (a
definite advantage if one of them is arrested). Dead drops can be used to
facilitate completely anonymous, asynchronous communications.
Using steganography to embed a message in a pornographic image and posting
it to a Usenet newsgroup is the cyberspace equivalent of a dead drop. To
everyone else, it's just a picture. But to the receiver, there's a message
in there waiting to be extracted.
To make it work in practice, the terrorists would need to set up some sort
of code. Just as Hanssen knew to collect his package when he saw the chalk
mark, a virtual terrorist will need to know to look for his message. (He
can't be expected to search every picture.) There are lots of ways to
communicate a signal: timestamp on the message, an uncommon word in the
subject line, etc. Use your imagination here; the possibilities are
limitless.
The effect is that the sender can transmit a message without ever
communicating directly with the receiver. There is no e-mail between them,
no remote logins, no instant messages. All that exists is a picture posted
to a public forum, and then downloaded by anyone sufficiently enticed by
the subject line (both third parties and the intended receiver of the
secret message).
So, what's a counter-espionage agency to do? There are the standard ways
of finding steganographic messages, most of which involve looking for
changes in traffic patterns. If Bin Laden is using pornographic images to
embed his secret messages, it is unlikely these pictures are being taken in
Afghanistan. They're probably downloaded from the Web. If the NSA can
keep a database of images (wouldn't that be something?), then they can find
ones with subtle changes in the low-order bits. If Bin Laden uses the same
image to transmit multiple messages, the NSA could notice that. Otherwise,
there's probably nothing the NSA can do. Dead drops, both real and
virtual, can't be prevented.
Why can't businesses use this? The primary reason is that legitimate
businesses don't need dead drops. I remember hearing one company talk
about a corporation embedding a steganographic message to its salespeople
in a photo on the corporate Web page. Why not just send an encrypted
e-mail? Because someone might notice the e-mail and know that the
salespeople all got an encrypted message. So send a message every day: a
real message when you need to, and a dummy message otherwise. This is a
traffic analysis problem, and there are other techniques to solve
it. Steganography just doesn't apply here.
Steganography is good way for terrorist cells to communicate, allowing
communication without any group knowing the identity of the other. There
are other ways to build a dead drop in cyberspace. A spy can sign up for a
free, anonymous e-mail account, for example. Bin Laden probably uses those
too.
News articles:
<http://www.wired.com/news/print/0,1294,41658,00.html>
<http://www.usatoday.com/life/cyber/tech/2001-02-05-binladen.htm>
<http://www.sfgate.com/cgi-bin/article.cgi?file=/gate/archive/2001/09/20/sig
intell.DTL>
<http://www.cnn.com/2001/US/09/20/inv.terrorist.search/>
<http://www.washingtonpost.com/wp-dyn/articles/A52687-2001Sep18.html>
My old essay on steganography:
<http://www.counterpane.com/crypto-gram-9810.html#steganography>
Study claims no steganography on eBay:
<http://www.theregister.co.uk/content/4/21829.html>
Detecting steganography on the Internet:
<http://www.citi.umich.edu/techreports/reports/citi-tr-01-11.pdf>
A version of this essay appeared on ZDnet:
<http://www.zdnet.com/zdnn/stories/comment/0,5859,2814256,00.html>
<http://www.msnbc.com/news/633709.asp?0dm=B12MT>
** *** ***** ******* *********** *************
News
I am not opposed to using force against the terrorists. I am not opposed
to going to war -- for retribution, deterrence, and the restoration of the
social contract -- assuming a suitable enemy can be
identified. Occasionally, peace is something you have to fight for. But I
think the use of force is far more complicated than most people
realize. Our actions are important; messing this up will only make things
worse.
Written before September 11: A former CIA operative explains why the
terrorist Usama bin Laden has little to fear from American intelligence.
<http://www.theatlantic.com/issues/2001/07/gerecht.htm>
And a Russian soldier discusses why war in Afghanistan will be a nightmare.
<http://www.latimes.com/news/printedition/asection/la-000075191sep19.story>
A British soldier explains the same:
<http://www.sunday-times.co.uk/news/pages/sti/2001/09/23/stiusausa02023.html
?>
Lessons from Britain on fighting terrorism:
<http://www.salon.com/news/feature/2001/09/19/fighting_terror/index.html>
1998 Esquire interview with Bin Ladin:
<http://www.esquire.com/features/articles/2001/010913_mfe_binladen_1.html>
Phil Agre's comments on these issues:
<http://commons.somewhere.com/rre/2001/RRE.War.in.a.World.Witho.html>
<http://commons.somewhere.com/rre/2001/RRE.Imagining.the.Next.W.html>
Why technology can't save us:
<http://www.osopinion.com/perl/story/13535.html>
Hactivism exacts revenge for terrorist attacks:
<http://news.cnet.com/news/0-1003-201-7214703-0.html?tag=owv>
FBI reminds everyone that it's illegal:
<http://www.nipc.gov/warnings/advisories/2001/01-020.htm>
<http://www.ananova.com/news/story/sm_400565.html?menu=>
Hackers face life imprisonment under anti-terrorism act:
<http://www.securityfocus.com/news/257>
Especially scary are the "advice or assistance" components. A security
consultant could face life imprisonment, without parole, if he discovered
and publicized a security hole that was later exploited by someone
else. After all, without his "advice" about what the hole was, the
attacker never would have accomplished his hack.
Companies fear cyberterrorism:
<http://cgi.zdnet.com/slink?140433:8469234>
<http://computerworld.com/nlt/1%2C3590%2CNAV65-663_STO63965_NLTSEC%2C00.html
>
They're investing in security:
<http://www.washtech.com/news/software/12514-1.html>
<http://www.theregister.co.uk/content/55/21814.html>
Upgrading government computers to fight terrorism:
<http://www.zdnet.com/zdnn/stories/news/0,4586,5096868,00.html>
Risks of cyberterrorism attacks against our electronic infrastructure:
<http://www.businessweek.com/bwdaily/dnflash/sep2001/nf20010918_8931.htm?&_r
ef=1732900718>
<http://cgi.zdnet.com/slink?143569:8469234>
Now the complaint is that Bin Laden is NOT using high-tech communications:
<http://www.theregister.co.uk/content/57/21790.html>
Larry Ellison is willing to give away the software to implement a national
ID card.
<http://www.siliconvalley.com/docs/news/svfront/ellsn092301.htm>
Security problems include: inaccurate information, insiders issuing fake
cards (this happens with state drivers' licenses), vulnerability of the
large database, potential privacy abuses, etc. And, of course, no
trans-national terrorists would be listed in such a system, because they
wouldn't be U.S. citizens. What do you expect from a company whose origins
are intertwined with the CIA?
** *** ***** ******* *********** *************
Protecting Privacy and Liberty
Appalled by the recent hijackings, many Americans have declared themselves
willing to give up civil liberties in the name of security. They've
declared it so loudly that this trade-off seems to be a fait
accompli. Article after article talks about the balance between privacy
and security, discussing whether various increases of security are worth
the privacy and civil-liberty losses. Rarely do I see a discussion about
whether this linkage is a valid one.
Security and privacy are not two sides of a teeter-totter. This
association is simplistic and largely fallacious. It's easy and fast, but
less effective, to increase security by taking away liberty. However, the
best ways to increase security are not at the expense of privacy and
liberty.
It's easy to refute the notion that all security comes at the expense of
liberty. Arming pilots, reinforcing cockpit doors, and teaching flight
attendants karate are all examples of security measures that have no effect
on individual privacy or liberties. So are better authentication of
airport maintenance workers, or dead-man switches that force planes to
automatically land at the closest airport, or armed air marshals traveling
on flights.
Liberty-depriving security measures are most often found when system
designers failed to take security into account from the beginning. They're
Band-aids, and evidence of bad security planning. When security is
designed into a system, it can work without forcing people to give up their
freedoms.
Here's an example: securing a room. Option one: convert the room into an
impregnable vault. Option two: put locks on the door, bars on the windows,
and alarm everything. Option three: don't bother securing the room;
instead, post a guard in the room who records the ID of everyone entering
and makes sure they should be allowed in.
Option one is the best, but is unrealistic. Impregnable vaults just don't
exist, getting close is prohibitively expensive, and turning a room into a
vault greatly lessens its usefulness as a room. Option two is the
realistic best; combine the strengths of prevention, detection, and
response to achieve resilient security. Option three is the worst. It's
far more expensive than option two, and the most invasive and easiest to
defeat of all three options. It's also a sure sign of bad planning;
designers built the room, and only then realized that they needed
security. Rather then spend the effort installing door locks and alarms,
they took the easy way out and invaded people's privacy.
A more complex example is Internet security. Preventive countermeasures
help significantly against script kiddies, but fail against smart
attackers. For a couple of years I have advocated detection and response
to provide security on the Internet. This works; my company catches
attackers -- both outside hackers and insiders -- all the time. We do it
by monitoring the audit logs of network products: firewalls, IDSs, routers,
servers, and applications. We don't eavesdrop on legitimate users or read
traffic. We don't invade privacy. We monitor data about data, and find
abuse that way. No civil liberties are violated. It's not perfect, but
nothing is. Still, combined with preventive security products it is more
effective, and more cost-effective, than anything else.
The parallels between Internet security and global security are
strong. All criminal investigation looks at surveillance records. The
lowest-tech version of this is questioning witnesses. In this current
investigation, the FBI is looking at airport videotapes, airline passenger
records, flight school class records, financial records, etc. And the
better job they can do examining these records, the more effective their
investigation will be.
There are copycat criminals and terrorists, who do what they've seen done
before. To a large extent, this is what the hastily implemented security
measures have tried to prevent. And there are the clever attackers, who
invent new ways to attack people. This is what we saw on September
11. It's expensive, but we can build security to protect against
yesterday's attacks. But we can't guarantee protection against tomorrow's
attacks: the hacker attack that hasn't been invented, or the terrorist
attack yet to be conceived.
Demands for even more surveillance miss the point. The problem is not
obtaining data, it's deciding which data is worth analyzing and then
interpreting it. Everyone already leaves a wide audit trail as we go
through life, and law enforcement can already access those records with
search warrants. The FBI quickly pieced together the terrorists'
identities and the last few months of their lives, once they knew where to
look. If they had thrown up their hands and said that they couldn't figure
out who did it or how, they might have a case for needing more surveillance
data. But they didn't, and they don't.
More data can even be counterproductive. The NSA and the CIA have been
criticized for relying too much on signals intelligence, and not enough on
human intelligence. The East German police collected data on four million
East Germans, roughly a quarter of their population. Yet they did not
foresee the peaceful overthrow of the Communist government because they
invested heavily in data collection instead of data interpretation. We
need more intelligence agents squatting on the ground in the Middle East
arguing the Koran, not sitting in Washington arguing about wiretapping laws.
People are willing to give up liberties for vague promises of security
because they think they have no choice. What they're not being told is
that they can have both. It would require people to say no to the FBI's
power grab. It would require us to discard the easy answers in favor of
thoughtful answers. It would require structuring incentives to improve
overall security rather than simply decreasing its costs. Designing
security into systems from the beginning, instead of tacking it on at the
end, would give us the security we need, while preserving the civil
liberties we hold dear.
Some broad surveillance, in limited circumstances, might be warranted as a
temporary measure. But we need to be careful that it remain temporary, and
that we do not design surveillance into our electronic
infrastructure. Thomas Jefferson once said: "Eternal vigilance is the
price of liberty." Historically, liberties have always been a casualty of
war, but a temporary casualty. This war -- a war without a clear enemy or
end condition -- has the potential to turn into a permanent state of
society. We need to design our security accordingly.
The events of September 11th demonstrated the need for America to redesign
our public infrastructures for security. Ignoring this need would be an
additional tragedy.
Quotes from U.S. government officials on the need to preserve liberty
during this crisis:
<http://www.epic.org/alert/EPIC_Alert_8.17.html>
Quotes from editorial pages on the same need:
<http://www.epic.org/alert/EPIC_Alert_8.18.html>
Selected editorials:
<http://www.nytimes.com/2001/09/16/weekinreview/16GREE.html>
<http://www.nytimes.com/2001/09/23/opinion/23SUN1.html>
<http://www.freedomforum.org/templates/document.asp?documentID=14924>
Schneier's comments in the UK:
<http://www.theregister.co.uk/content/55/21892.html>
War and liberties:
<http://www.salon.com/tech/feature/2001/09/22/end_of_liberty/index.html>
<http://www.washingtonpost.com/wp-dyn/articles/A21207-2001Sep12.html>
<http://www.wired.com/news/politics/0,1283,47051,00.html>
More on Ashcroft's anti-privacy initiatives:
<http://www.theregister.co.uk/content/6/21854.html>
Editorial cartoon:
<http://www.claybennett.com/pages/latest_08.html>
Terrorists leave a broad electronic trail:
<http://www.wired.com/news/politics/0,1283,46991,00.html>
National Review article from 1998: "Know nothings: U.S. intelligence
failures stem from too much information, not enough understanding"
<http://www.findarticles.com/m1282/n14_v50/21102283/p1/article.jhtml>
A previous version of this essay appeared in the San Jose Mercury News:
<http://www0.mercurycenter.com/premium/opinion/columns/security27.htm>
** *** ***** ******* *********** *************
How to Help
How can you help? Speak about the issues. Write to your elected
officials. Contribute to organizations working on these issues.
This week the United States Congress will act on the most sweeping proposal
to extend the surveillance authority of the government since the end of the
Cold War. If you value privacy, there are three steps you should take
before you open your next email message:
1. Urge your representatives in Congress to protect privacy.
- Call the White House switchboard at 202-224-3121.
- Ask to be connected to the office of your Congressional representative.
- When you are put through, say "May I please speak to the staff member who
is working on the anti-terrorism legislation?" If that person is not
available to speak with you, say "May I please leave a message?"
- Briefly explain that you appreciate the efforts of your representative to
address the challenges brought about by the September 11th tragedy, but it
is your view that it would be a mistake to make any changes in the federal
wiretap statute that do not respond to "the immediate threat of
investigating or preventing terrorist acts."
2. Go to the In Defense of Freedom web site and endorse the
statement: <http://www.indefenseoffreedom.org>
3. Forward this message to at least five other people.
We have less than 100 hours before Congress acts on legislation that will
(a) significantly expand the use of Carnivore, (b) make computer hacking a
form of terrorism, (c) expand electronic surveillance in routine criminal
investigations, and (d) reduce government accountability.
Please act now.
More generally, I expect to see many pieces of legislation that will
address these matters. Visit the following Web sites for up-to-date
information on what is happening and what you can do to help.
The Electronic Privacy Information Center:
<http://www.epic.org>
The Center for Democracy and Technology:
<http://www.cdt.org>
The American Civil Liberties Union:
<http://www.aclu.org>
** *** ***** ******* *********** *************
CRYPTO-GRAM is a free monthly newsletter providing summaries, analyses,
insights, and commentaries on computer security and cryptography. Back
issues are available on <http://www.counterpane.com/crypto-gram.html>.
To subscribe, visit <http://www.counterpane.com/crypto-gram.html> or send a
blank message to [log in to unmask] To unsubscribe,
visit <http://www.counterpane.com/unsubform.html>.
Please feel free to forward CRYPTO-GRAM to colleagues and friends who will
find it valuable. Permission is granted to reprint CRYPTO-GRAM, as long as
it is reprinted in its entirety.
CRYPTO-GRAM is written by Bruce Schneier. Schneier is founder and CTO of
Counterpane Internet Security Inc., the author of "Secrets and Lies" and
"Applied Cryptography," and an inventor of the Blowfish, Twofish, and
Yarrow algorithms. He is a member of the Advisory Board of the Electronic
Privacy Information Center (EPIC). He is a frequent writer and lecturer on
computer security and cryptography.
Counterpane Internet Security, Inc. is the world leader in Managed Security
Monitoring. Counterpane's expert security analysts protect networks for
Fortune 1000 companies world-wide.
<http://www.counterpane.com/>
Copyright (c) 2001 by Counterpane Internet Security, Inc.
************************************************************************************
Distributed through Cyber-Society-Live [CSL]: CSL is a moderated discussion
list made up of people who are interested in the interdisciplinary academic
study of Cyber Society in all its manifestations.To join the list please visit:
http://www.jiscmail.ac.uk/lists/cyber-society-live.html
*************************************************************************************
|
