CRYPTO-GRAM, June 15, 2002

                  CRYPTO-GRAM

                  June 15, 2002

               by Bruce Schneier
                Founder and CTO
       Counterpane Internet Security, Inc.
            [email protected]
          <http://www.counterpane.com>


A free monthly newsletter providing summaries, analyses, insights, and 
commentaries on computer security and cryptography.

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 
[email protected].

Copyright (c) 2002 by Counterpane Internet Security, Inc.


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In this issue:
      Fixing Intelligence Failures
      Crypto-Gram Reprints
      News
      Counterpane News
      More on Secrecy and Security
      Comments from Readers


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          Fixing Intelligence Failures



Could the intelligence community have connected the dots?  Why didn't 
anyone connect the dots?  How can we make sure we connect the dots next 
time?  Dot connecting is the metaphor of the moment in Washington, as the 
various politicians scramble to make sure that 1) their pet ideas for 
improving domestic security are adopted, and 2) they don't get blamed for 
any dot connection failures that could have prevented 9/11.

Unfortunately, it's the wrong metaphor.  We all know how to connect the 
dots.  They're right there on the page, and they're all numbered.  All you 
have to do is move your crayon from one dot to another, and when you're 
done you've drawn a lion.  It's so easy a three-year-old could do it; 
what's wrong with the FBI and the CIA?

The problem is that the dots can only be numbered after the fact.  With the 
benefit of hindsight, it's easy to draw lines from people in flight school 
here, to secret meetings in foreign countries there, over to interesting 
tips from foreign governments, and then to INS records.  Before 9/11 it's 
not so easy.  Rather than thinking of intelligence as a simple 
connect-the-dots picture, think of it as a million unnumbered pictures 
superimposed on top of each other.  Or a random-dot stereogram.  Is it a 
lion, a tree, a cast iron stove, or just an unintelligible mess of 
dots?  You try and figure it out.

This isn't to say that the United States didn't have some spectacular 
failures in analysis leading up to 9/11.  Way back in the 30 September 2001 
issue of Crypto-Gram, I wrote: "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."  I was guessing there.  It seems that there was more than 
I thought.

Given the bits of information that have been discussed in the press, I 
would have liked to think that we could have prevented this one, that there 
was a single Middle Eastern Terrorism desk somewhere inside the 
intelligence community whose job it was to stay on top of all of this.  It 
seems that we couldn't, and that there wasn't.  A budget issue, most likely.

Still, I think the "whose fault is it?" witch hunt is a bit much.  Not that 
I mind seeing George Bush on the defensive.  I've gotten sick of his "we're 
at war, and if you criticize me you're being unpatriotic" nonsense, and I 
think the enormous damage John Ashcroft has done to our nation's freedoms 
and liberties will take a generation and another Warren Court to fix.  But 
all this finger-pointing between the CIA and FBI is childish, and I'm 
embarrassed by the Democrats who are pushing through their own poorly 
thought out security proposals so they're not viewed in the polls as being 
soft on terrorism.

My preference is for less politics and more intelligent discussion.  And 
I'd rather see the discussion center on how to improve things for next 
time, rather than on who gets the blame for this time.  So, in the spirit 
of bipartisanship (there are plenty of nitwits in both parties), here are 
some points for discussion:

1.  It's not about data collection; it's about data analysis.  Again from 
the 30 September 2001 issue of Crypto-Gram: "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 [and 
subpoenas].  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."

2.  Security decisions need to be made as close to the source as 
possible.  This has all sorts of implications: airport X-ray machines 
should be right next to the departure gates, like they are in some European 
airports; bomb target decisions should be made by the generals on the 
ground in the war zone, not by some bureaucrat in Washington; and 
investigation approvals should be granted the FBI office that's closest to 
the investigation.  This mode of operation has more opportunities for 
abuse, so oversight is vital.  But it is also more robust, and the best way 
to make things work.  (The U.S. Marine Corps understands this principle; 
it's the heart of their chain of command rules.)

3.  Data correlation needs to happen as far away from the sources as 
possible.  Good intelligence involves finding meaning amongst enormous 
reams of irrelevant data, and then organizing all those disparate pieces of 
information into coherent predictions about what will happen next.  It 
requires smart people who can see connections, and access to information 
from many different branches of government.  It can't be by the various 
individual pieces of bureaucracy, whether it be the CIA, FBI, NSA, INS, 
Coast Guard, etc.  The whole picture is larger than any of them, and each 
one only has access to a small piece.

4.  Intelligence and law enforcement have fundamentally different 
missions.  The FBI's model of operation -- investigation of past crimes -- 
does not lend itself to an intelligence paradigm: prediction of future 
events.  On the other hand, the CIA is prohibited by law from spying on 
citizens.  Expecting the FBI to become a domestic CIA is a terrible idea; 
the missions are just too different and that's too much power to 
consolidate under one roof.  Turning the CIA into a domestic intelligence 
agency is an equally terrible idea; the tactics that they regularly use 
abroad are unconstitutional here.

5.  Don't forget old-fashioned intelligence gathering.  Enough with the 
Echelon-like NSA programs where everything and anything gets sucked into an 
enormous electronic maw, never to be looked at again.  Lots of Americans 
managed to become part of Al Qaeda (a 20-year-old Californian did it, for 
crying out loud); why weren't any of them feeding intelligence to the 
CIA?  Get out in the field and do your jobs.

6.  Organizations with investigative powers require constant oversight.  If 
we want to formalize a domestic intelligence agency, we are going to need 
to be very careful about how we do it.  Many of the checks and balances 
that Ashcroft is discarding were put in place to prevent abuse.  And abuse 
is rampant -- at the federal, state, and local levels.  Just because 
everyone is feeling good about the police today doesn't mean that things 
won't change in the future.  They always do.

7.  Fundamental changes in how the United States copes with domestic 
terrorism requires, um, fundamental changes.  Much as the Bush 
Administration would like to ignore the constitutional issues surrounding 
some of their proposals, those issues are real.  Much of what the Israeli 
government does to combat terrorism in its country, even some of what the 
British government does, is unconstitutional in the United 
States.  Security is never absolute; it always involved tradeoffs.  If 
we're going to institute domestic passports, arrest people in secret and 
deny them any rights, place people with Arab last names under continuous 
harassment, or methodically track everyone's financial dealings, we're 
going to have to rewrite the Constitution.  At the very least, we need to 
have a frank and candid debate about what we're getting for what we're 
giving up.  People might want to live in a police state, but let them at 
least decide willingly to live in a police state.  My opinion has been that 
it is largely unnecessary to trade civil liberties for security, and that 
the best security measures -- reinforcing the airplane cockpit door, 
putting barricades and guards around important buildings, improving 
authentication for telephone and Internet banking -- have no effect on 
civil liberties.  Broad surveillance is a mark of bad security.

All in all, I'm not sure how the Department of Homeland Security is going 
to help with any of this.  Taking a bunch of ineffectual little 
bureaucracies and lumping them together into a single galumptious 
bureaucracy doesn't seem like a step in the right direction.  Leaving the 
FBI and CIA out of the mix -- the largest sources of both valuable 
information and turf-based problems -- doesn't help, either.  And if the 
individual organizations squabble and refuse to share information, 
reshuffling the chain of command isn't really going to make any difference 
-- it'll just add needless layers of management.  And don't forget the $37 
billion this is all supposed to cost, assuming there aren't the usual 
massive cost overruns.  Couldn't we better spend that money teaching Arabic 
to case officers, hiring investigators, and doing various things that 
actually will make a difference?

The problems are about politics and policy, and not about form and 
structure.  Fix the former, and fixing the latter becomes easy.  Change the 
latter without fixing the former, and nothing will change.

I'm not denying the need for some domestic intelligence capability.  We 
need something to respond to future domestic threats.  I'm not happy with 
this conclusion, but I think it may be the best of a bunch of bad 
choices.  Given this, the thing to do is make sure we approach that choice 
correctly, paying attention to constitutional protections, respecting 
privacy and civil liberty, and minimizing the inevitable abuses of power.

My original articles:
<http://www.counterpane.com/crypto-gram-0109a.html#4>
<http://www.counterpane.com/crypto-gram-0109a.html#8>


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             Crypto-Gram Reprints



Crypto-Gram is currently in its fifth year of publication.  Back issues 
cover a variety of security-related topics, and can all be found on 
<http://www.counterpane.com/crypto-gram.html>.  These are a selection of 
articles that appeared in this calendar month in other years.

Honeypots and the Honeynet Project
<http://www.counterpane.com/crypto-gram-0106.html#1>

Microsoft SOAP:
<http://www.counterpane.com/crypto-gram-0006.html#SOAP>

The Data Encryption Standard (DES):
<http://www.counterpane.com/crypto-gram-0006.html#DES>

The internationalization of cryptography policy:
<http://www.counterpane.com/crypto-gram-9906.html#policy>
and products:
<http://www.counterpane.com/crypto-gram-9906.html#products>

The new breeds of viruses, worms, and other malware:
<http://www.counterpane.com/crypto-gram-9906.html#viruses>

Timing attacks, power analysis, and other "side-channel" attacks against 
cryptosystems:
<http://www.counterpane.com/crypto-gram-9806.html#side>


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                      News



More biometric articles:
<http://www.anu.edu.au/people/Roger.Clarke/DV/NotesCFP02.html#BiomRC>
<http://www.anu.edu.au/people/Roger.Clarke/DV/BiomHKU.ppt>

And yet another:
<http://chris.fornax.net/download/thesis/thesis.pdf>

This is a particularly good article about failures in biometric sensors:
<http://www.heise.de/ct/english/02/11/114/>

And another one about fingerprints:
<http://keuning.com/biometry>

The Matsumoto paper I talked about last month is here:
<http://cryptome.org/gummy.htm>
And there are some news stories on my story in Crypto-Gram.  (I think this 
counts as my first "scoop.")
<http://news.com.com/2100-1001-915580.html>
<http://www.theregus.com/content/55/24956.html>
<http://news.zdnet.co.uk/story/0,,t269-s2110380,00.html>
<http://news.bbc.co.uk/hi/english/sci/tech/newsid_1991000/1991517.stm>
<http://research.yale.edu/lawmeme/modules.php?name=News&file=article&sid=214>
In response, various fingerprint companies have issued statements claiming 
that they're not vulnerable to the attack for a variety of 
reasons.  Remember the point of the story, though.  Matsumoto is not a 
professional forensic scientist.  Even so, with a little bit of ingenuity 
and some common household products, he was able to reliably defeat eleven 
commercial fingerprint readers from latent fingerprints.  If he could do 
this, what would he do with a budget of $50?  What could he do with a few 
more weeks of thinking?  What could a professional in the field 
do?  Fingerprint-sensor vendors have long claimed that their products could 
not be spoofed.  Why would anyone believe them when they say it now?

And as long as we're on the topic, consider whether Matsumoto's procedure 
for making gummi fingers could be used to leave a latent fingerprint that 
might fool the police.

High-speed worms, and a discussion on defenses:
<http://www.cs.berkeley.edu/~nweaver/cdc.web/>

Virtual credit cards.  Randomized numbers for safer online shopping.  Done 
correctly, this is a really good idea.
<https://www.citibank.com/us/cards/tour/cmc_van.htm>
Remember, the real risks here are not sending credit card numbers in the 
clear over the Internet; they're the databases of credit card numbers 
stored in merchant computers.

Airport face scanners a dismal failure:
<http://www.wired.com/news/privacy/0,1848,52563,00.html>
The system failed to correctly identify airport employees 53 percent of the 
time.  And this is with standardized, high-quality photographs to start 
with.  Imagine the system trying to work with grainy photographs of 
suspected terrorists.

For computer eavesdropping.  This nifty hardware device sits between the 
keyboard and the computer, where no one will think of looking for it, and 
captures keystrokes for later analysis.  Every spy needs one.
<http://www.thinkgeek.com/stuff/gadgets/5a05.shtml>

Keystroke logging was used by FBI to catch two Russian hackers.  No details 
on whether it was hardware or software, or administered locally or remotely.
<http://www.cbsnews.com/stories/2002/05/14/eveningnews/main508953.shtml>

Video forgery.  Make video recordings of people saying things they've never 
said:
<http://www.paramount.com/television/babybob/>
<http://www.boston.com/dailyglobe2/135/metro/At_MIT_they_can_put_words_in_ou 
r_mouths+.shtml>

NIST Report:  The Economic Impact of Role-Based Access Control.  Another 
example of the interplay of economics and security.
<http://www.nist.gov/director/prog-ofc/report02-1.pdf>

Article on the buying and selling of stolen credit card numbers:
<http://www.siliconvalley.com/mld/siliconvalley/news/editorial/3252532.htm>
I believe that everyone has, in his wallet right now, a credit card number 
that has been stolen.  Almost none of those stolen numbers will ever be 
bought, sold, or used.  There are just too many large databases of credit 
card numbers on Internet-accessible computers, and they're probably all 
insecure.  It's a good thing this isn't my liability.

"Photo flash" attacks against smart cards.  (Yet another way to break smart 
cards.)
<http://www.nwfusion.com/news/2002/0514smartcards.html>
<http://slashdot.org/articles/02/05/13/1355204.shtml?tid=172>
The paper:
<http://www.ftp.cl.cam.ac.uk/ftp/users/rja14/faultpap3.pdf>

And yet another way to eavesdrop on CRT displays:
<http://www.cl.cam.ac.uk/~mgk25/emsec/optical-faq.html>

Politically motivated hacking:
<http://www.newsfactor.com/perl/story/17763.html>

Microsoft's "Trustworthy Computing" initiative seems to be just a scam so 
the company can avoid antitrust remedies by claiming that opening their 
systems is a security risk.  Pity.
<http://www.eweek.com/article/0,3658,s=701%26a=26605,00.asp>
<http://www.eweek.com/article/0,3658,s%253D701%2526a%253D26875,00.asp>
A comment on Slashdot sums it up best: "Microsoft has therefore taken the 
position that their code is so bad that it must be kept secret to keep 
people from being killed by it.  Windows -- the Pinto of the 21st century."

Most interesting of the two articles above is the second eWeek article, 
where Microsoft's Allchin mentions "at least one protocol and two APIs that 
it plans to withhold from public disclosure under the security 
carve-out."  The protocol is Message Queuing.  Apparently, Microsoft has 
discovered a security flaw in the Message Queuing protocol so bad that 
can't be fixed without breaking existing applications.  So, until such time 
as they can field a backwards-compatible fix, they're going to hope no one 
else discovers it.  (This is not a wholly unreasonable decision; security 
researchers have made the same decision in the past.)  Of course, Allchin 
has undermined this decision by publicly naming the protocol.  That's more 
than enough for someone sufficiently motivated to find the flaw.  In the 
classified world, you can get your clearance pulled for blabbing like that.
Jim Allchin's testimony:
<http://www.microsoft.com/presspass/trial/mswitness/2002/allchin.asp>

At the same time, Microsoft tries to convince the Pentagon that open source 
software threatens security, and using proprietary Microsoft software is 
much safer (and better for the economy, to boot).  This article is 
hilarious in light of the above.
<http://www.washingtonpost.com/wp-dyn/articles/A60050-2002May22.html>

A white paper that makes the case that open source software is less 
secure.  However, it's from a group that has received funding from Microsoft.
<http://zdnet.com.com/2100-1104-929669.html>
<http://www.theregister.co.uk/content/4/25656.html>
<http://www.adti.net/html_files/defense/opensource_whitepaper.pdf>

Good essay on security negligence:
<http://www.gigaweb.com/content_display/popup/1,,PubID=MCO-052002-00001,00.h 
tml>

Thousands illegally obtain fraudulent Social Security numbers in the United 
States.  Any reason to believe a national ID card would be any less 
abuse-prone?
<http://www.nytimes.com/2002/05/20/national/20FRAU.html>

Attacks against Yahoo:
<http://www.ddj.com/news/fullstory.cgi?id=5887>

Defeating copy-protected CDs with a magic marker.  What bozos design these 
security systems, anyway?
<http://news.com.com/2100-1023-918273.html>

An analysis of Bernstein's factoring proposal.  I agree with this paper; 
there's less in the proposal than appears.
<http://www.cryptosavvy.com/mesh.pdf>
<http://www.cryptosavvy.com/mesh.ps>
<http://slashdot.org/article.pl?sid=02/06/04/1936239&mode=thread&tid=93>

Interview with a senior architect of the Echelon project:
<http://cryptome.org/echelon2-arch.htm>

Passwords still suck:
<http://news.com.com/2009-1001-916719.html>

I've already written about how UNICODE can evade IDSs.  Here's another 
essay on the topic:
<http://online.securityfocus.com/infocus/1232>

FBI agents sell a stock short, and then leak unpleasant personal 
information about the corporate officers.  Other companies are blackmailed 
with threat of the same.
<http://slashdot.org/articles/02/05/22/2347219.shtml?tid=158>

Thomas Friedman writes in the New York Times:  "Silicon Valley staunchly 
opposed the Clipper Chip, which would have given the government a back-door 
key to all U.S. encrypted data.  Now some wonder whether they shouldn't 
have opposed it.  John Doerr, the venture capitalist, said, 'Culturally, 
the Valley was already maturing before 9/11, but since then it's definitely 
developed a deeper respect for leaders and government 
institutions.'"  That's completely wrong.  We opposed Clipper not because 
we don't trust the government, but because we don't trust the 
technology.  Respect is not sufficient to make complex systems secure.
<http://www.nytimes.com/2002/05/26/opinion/26FRIE.html>
Via Usenet, so no annoying registration:
<http://groups.google.com/groups?q=clipper+doerr&hl=en&lr=&ie=utf-8&oe=utf-8 
&scoring=d&selm=3CF2A8C2.10145.2B3C2394%40localhost&rnum=1>

Interesting paper on the relationship between user interface and security:
<http://zesty.ca/sid>

Protecting your privacy online, a four-part article:
<http://online.securityfocus.com/infocus/1568>
<http://online.securityfocus.com/infocus/1573>
<http://online.securityfocus.com/infocus/1579>
<http://online.securityfocus.com/infocus/1585>

Japanese hackers arrested for industrial spying.
<http://europe.cnn.com/2002/WORLD/asiapcf/east/05/30/japan.spacehackers.ap/i 
ndex.html>

The story of a rather lame hacking contest gone badly wrong:
<http://zdnet.com.com/2100-1105-930689.html>
<http://news.zdnet.co.uk/story/0,,t269-s2111243,00.html>

A report on something called a Tactical Web Page, which purports to be a 
secret combat Web site, through which American commanders in the United 
States can direct troops in Afghanistan.  My favorite quote:  "'There have 
been a few instances when unidentified computers have tried to get in, in 
which case we throw up additional firewalls,' Lt. Col. Bryan Dyer 
said."  Is it just me, or does Lt. Col. Dyer come from I-Don't-Get-It Land?
<http://www.wired.com/news/politics/0,1283,52861,00.html>

Yet more comments from the clueless.  In response to the report that 
someone hacked into Experian's database and stole 13,000 credit-card 
numbers, a PR flack said:  "Our files are protected by state-of-the-art, 
Star Wars-style security and encryption technology."
<http://www.lendingintelligence.com/news.ez?viewStory=1123&Form.sess_id=8455 
21234&Form.sess_key=1022430845>

And this review of PGP.  "PGP's basic encryption is about 10 times higher 
than that of other apps" -- but only if you compare RSA with 
triple-DES.  "Fortunately, PGP includes a primer on encryption 
principles.  Read the primer carefully, and you'll rev right up to 
speed."  Maybe the reviewer should read it, too.
<http://www.cnet.com/software/0-806183-8-4792641-2.html>

VeriSign is offering companies the ability to outsource their compliance 
with U.S. Internet wiretap regulations.  They will comply with government 
wiretap court orders, so companies don't have to redesign their 
infrastructure.  I've seen a lot of VeriSign-bashing over this, but I think 
it's a fine example of a company stepping in and filling a market 
need.  VeriSign wants to be the trusted infrastructure company, and this is 
just another aspect of that.  Complain about the U.S. law, not the vehicle 
for compliance.
<http://corporate.verisign.com/news/2002/pr_20020603a.html>
<http://www.siliconvalley.com/mld/siliconvalley/news/editorial/3391113.htm>

Amusing story of lousy passwords at the New York Times:
<http://www.oreillynet.com/cs/weblog/view/wlg/1482>

NIST wants comments on Part 1 of their Key Management Guidelines:
<http://www.nist.gov/kms>

Hacking for good.  Password cracked; Norwegian history saved!
<http://news.com.com/2100-1001-934060.html>

Microsoft's editorial on government-mandated digital copy protection.  I 
actually agree with a lot of this.
<http://www.microsoft.com/issues/essays/2002/06-03digitalrights.asp>

Hacking the Xbox.  Interesting stuff, especially the fact that the security 
is based on a single global secret.  Hack one box, hack them all.
<http://news.com.com/2100-1040-931296.html>
<http://www.theregus.com/content/3/25130.html>
<ftp://publications.ai.mit.edu/ai-publications/2002/AIM-2002-008.pdf>
<http://web.mit.edu/bunnie/www/proj/anatak/xboxmod.html>

Using a cell phone as a room bug:
<http://www.cnn.com/2002/TECH/ptech/06/11/israel.netline.reut/index.html>

ASN.1 security:
<http://online.securityfocus.com/news/474>
<http://online.wsj.com/article_email/0,,SB1023731908761703280,00.html>


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                Counterpane News


More news on the VeriSign/Counterpane agreement:
<http://www.counterpane.com/pr-verisign.html>

A good article about Counterpane from Computerworld:
<http://www.computerworld.com/securitytopics/security/story/0,10801,71773,00 
.html>

Schneier is speaking about Counterpane monitoring in California (Anaheim 
and Irvine, both near Los Angeles), Dallas, and Cincinnati.  For details see:
<http://www.counterpane.com/conf.html>


** *** ***** ******* *********** *************

         More on Secrecy and Security



In case you think this is an easy issue, here's something to mull over.

The New York Times Magazine recently carried a fascinating article on the 
terrorist threat -- myths and realities -- of a nuclear bomb.  The article 
talks about one atomic researcher's nightmare scenario: a homemade nuclear 
explosive device being detonated in New York.  The researcher suggests that 
the attackers would detonate the device inside a tunnel, because that 
"would vaporize many tons of concrete and dirt and river water into an 
enduring cloud of lethal fallout."

My reactions were 1) now that's clever, 2) I never thought of that, and 3) 
should he have published that?  I have to admit that I don't know.

Information about poisons is kept relatively secret.  I'm sure there are 
sites on the Internet -- however, we all know how accurate the Internet can 
be -- but doctors are generally reluctant to divulge recipes to the general 
public.  Those in the field know, but there's little benefit to announcing 
the information to every would-be killer.

Nuclear information is different.  It's possible that anyone with enough 
skill to create a home-made nuclear bomb already knows about the "detonate 
it in a tunnel" trick, and a dozen other tricks that I, without any 
specialized education, doesn't.  It's also possible that the average 
amateur nuclear warrior would never think of it.  I don't know.

<http://www.nytimes.com/2002/05/26/magazine/26NUKES.html>


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             Comments from Readers



From: Bob Chase <[email protected]>
Subject:  Secrecy, Security, and Obscurity

I accept your general argument wholeheartedly, but this corollary has a 
gotcha.  Secrets can work in parallel or in serial.

For instance, suppose we want to gain root on a box to which we have 
physical access.  There are several "secrets" that we might try (boot from 
CD, special boot parameters, guessing screen saver passwords, etc).  If any 
of these methods works, then security is compromised; each of these methods 
works in parallel.

Suppose instead that the box is in a room with a secret combination which 
is in a building with a secret combination.  We have a serial combination 
of secrets, which will continue to hold -- in a weaker state -- if any one 
secret is known.

Again, I think what you are saying is important, and needs to be said!  And 
the systems that you use as examples are good examples of bad combinations 
of parallel secrets!  I simply think that there is a case for strengthening 
security through multiple serial secrets.



From: Pekka Pihlajasaari <[email protected]>
Subject: Secrecy, Security, and Obscurity

Kerckhoffs' principle "in a well-designed cryptographic system, only the 
key needs to be secret" is not necessarily reflexive, and makes no 
statement about aspects other than the key.  While non-disclosure may 
restrict the validation of the algorithms, it does not necessarily reduce 
the security of the system.

Whereas a key is an independent value, a cryptographic algorithm may result 
in artifacts, and information about it could be inferred through analysis 
of the encrypted text.  As such, security based on secrecy of the algorithm 
may be discounted in an analysis of a system.  There is no need to invoke 
quality or correctness arguments to show the futility of suppressing the 
choice of the algorithm as a security measure.

This principle can be generalised to other environments when the algorithm 
forms a part of a cryptographic system where the economic value is 
exclusively embodied in the key.  In many cases competitive advantage is 
derived from the algorithm in the form of limiting markets through export 
restrictions, or reduced credit default exposure.  Such systems provide 
benefits outside the scope of pure cryptographic protocols and should be 
analysed separately.

Your observation "the fewer secrets a system has, the more secure it is" is 
a corollary.  If the secrets are keys, then they may be coalesced into a 
single key, giving the traditional interpretation of a system with an 
algorithm and a single key.  Otherwise, the system has multiple secrets 
that are not keys, but components of a business process (the algorithm) 
that is inferable and not possible to secure.  Given sufficient willing 
participants it is possible to determine the threshold of an airport 
security sensor, and even the placement of mines in a mine field, allowing 
reverse-engineering of a security process.

It may be better to state that if a system can contains a single secret, 
then full disclosure does not affect its security and simply introduces 
obscurity, whereas if other information needs to be secured, secrecy is 
necessary, but not sufficient for continued protection against disclosure 
through inference.



From: [email protected]
Subject: Fun with Fingerprint Readers

Matsumoto-san is most likely not using what Americans would purchase in 
groceries as gelatin, which is definitely not stable at room temperature or 
higher.  Have you ever seen a Jell-O salad at a picnic on a hot summer 
day?  Not a pretty sight, even if you fortify it.

Matsumoto-san is more likely using kanten, commonly known in English as 
"agar-agar."  This is a sea vegetable gelatin which does not need to be 
refrigerated and is quite hard at room temperature.  (Kanten is the 
Japanese name for the product; I do not know what it is called in other 
Asian languages.)  Kanten can be purchased at Asian groceries in sheets, 
strips, or powder: cook's choice as to which you find easiest to work 
with.  Personally, I find the powder easiest.



From: Gunnar Peterson <[email protected]>
Subject: Web Services and SOAP

One thing that I have heard you mention before that I disagree with is that 
Web Services and things like SOAP are bad for security.

First off, any technology will have some security issues and Web Services 
are no different, but this does not mean that they are "bad," because you 
have to look at what they are replacing.  If I am writing a distributed app 
today that needs to traverse the firewall or WAN my choices are RMI-IIOP 
(J2EE or CORBA) or DCOM (Microsoft) or some type of proprietary messaging 
system.

As you have often said, complexity is the enemy of security...well...Web 
Services represent a much more simplistic approach to distributed app 
development.  For one thing I can use SOAP in either a J2EE or .Net app, so 
the security team only needs to understand this one protocol to be useful 
to either style of development team (for the distributed programming part 
of the project).

For another thing, Web Services and SOAP are a shift away from code and 
towards semantic meaning (as Don Box says) and this also aids the 
understanding of a complex system.  Given a good architect, development, 
and security team, a Web Services-based system has a better chance at being 
secure in development and production than RMI-IIOP- or DCOM-based apps.

So I would say that Web Services and SOAP are an imperfect yet incremental 
improvement over the current situation.



From: Glenn Welt <[email protected]>
Subject: 10 Day Notice: Welt vs. Counterpane & Schneier

I hereby request the immediate removal of false & defamatory comments about 
my software, ChecksNet, from the following website within ten days of this 
notice:

http://www.counterpane.com/crypto-gram-9906.html#doghouse2

Be sure to also remove all mirror sites containing the same false and 
defamatory statements.

My website, checksnet.com offers both secure SSL order pages and non-secure 
order pages, thus your accusations are totally false.  Whereas your 
defamatory pages appear via numerous search engines, it is damaging to the 
reputation and sales of my software.

This is not an empty threat.  In the past 2 years I have taken people to 
court and been awarded 6 figure judgments for defamation.

This will be my only notice prior to commencement of legal action.

I suggest removing the "doghouse" editorials unless you wish to personally 
and corporately appear in a "courthouse."


** *** ***** ******* *********** *************


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