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<h1><a name="politics">History and politics of cryptography</a></h1>
<p>Cryptography has a long and interesting history, and has been the subject
of considerable political controversy.</p>
<h2><a name="intro.politics">Introduction</a></h2>
<h3>History</h3>
<p>The classic book on the history of cryptography is David Kahn's <a
href="biblio.html#Kahn">The Codebreakers</a>. It traces codes and
codebreaking from ancient Egypt to the 20th century.</p>
<p>Diffie and Landau <a href="biblio.html#diffie">Privacy on the Line: The
Politics of Wiretapping and Encryption</a> covers the history from the First
World War to the 1990s, with an emphasis on the US.</p>
<h4>World War II</h4>
<p>During the Second World War, the British "Ultra" project achieved one of
the greatest intelligence triumphs in the history of warfare, breaking many
Axis codes. One major target was the Enigma cipher machine, a German device
whose users were convinced it was unbreakable. The American "Magic" project
had some similar triumphs against Japanese codes.</p>
<p>There are many books on this period. See our bibliography for several. Two
I particularly like are:</p>
<ul>
<li>Andrew Hodges has done a superb <a
href="http://www.turing.org.uk/book/">biography</a> of Alan Turing, a key
player among the Ultra codebreakers. Turing was also an important
computer pioneer. The terms <a
href="http://www.abelard.org/turpap/turpap.htm">Turing test</a> and <a
href="http://plato.stanford.edu/entries/turing-machine/">Turing
machine</a> are named for him, as is the <a
href="http://www.acm.org">ACM</a>'s highest technical <a
href="http://www.acm.org/awards/taward.html">award</a>.</li>
<li>Neal Stephenson's <a href="biblio.html#neal">Cryptonomicon</a> is a
novel with cryptography central to the plot. Parts of it take place
during WW II, other parts today.</li>
</ul>
<p>Bletchley Park, where much of the Ultra work was done, now has a museum
and a <a href="http://www.bletchleypark.org.uk/">web site</a>.</p>
<p>The Ultra work introduced three major innovations.</p>
<ul>
<li>The first break of Enigma was achieved by Polish Intelligence in 1931.
Until then most code-breakers had been linguists, but a different
approach was needed to break machine ciphers. Polish Intelligence
recruited bright young mathematicians to crack the "unbreakable" Enigma.
When war came in 1939, the Poles told their allies about this, putting
Britain on the road to Ultra. The British also adopted a mathematical
approach.</li>
<li>Machines were extensively used in the attacks. First the Polish "Bombe"
for attacking Enigma, then British versions of it, then machines such as
Collosus for attacking other codes. By the end of the war, some of these
machines were beginning to closely resemble digital computers. After the
war, a team at Manchester University, several old Ultra hands included,
built one of the world's first actual general-purpose digital
computers.</li>
<li>Ultra made codebreaking a large-scale enterprise, producing
intelligence on an industrial scale. This was not a "black chamber", not
a hidden room in some obscure government building with a small crew of
code-breakers. The whole operation -- from wholesale interception of
enemy communications by stations around the world, through large-scale
code-breaking and analysis of the decrypted material (with an enormous
set of files for cross-referencing), to delivery of intelligence to field
commanders -- was huge, and very carefully managed.</li>
</ul>
<p>So by the end of the war, Allied code-breakers were expert at large-scale
mechanised code-breaking. The payoffs were enormous.</p>
<h4><a name="postwar">Postwar and Cold War</a></h4>
<p>The wartime innovations were enthusiastically adopted by post-war and Cold
War signals intelligence agencies. Presumably many nations now have some
agency capable of sophisticated attacks on communications security, and quite
a few engage in such activity on a large scale.</p>
<p>America's <a href="glossary.html#NSA">NSA</a>, for example, is said to be
both the world's largest employer of mathematicians and the world's largest
purchaser of computer equipment. Such claims may be somewhat exaggerated, but
beyond doubt the NSA -- and similar agencies in other countries -- have some
excellent mathematicians, lots of powerful computers, sophisticated software,
and the organisation and funding to apply them on a large scale. Details of
the NSA budget are secret, but there are some published <a
href="http://www.fas.org/irp/nsa/nsabudget.html">estimates</a>.</p>
<p>Changes in the world's communications systems since WW II have provided
these agencies with new targets. Cracking the codes used on an enemy's
military or diplomatic communications has been common practice for centuries.
Extensive use of radio in war made large-scale attacks such as Ultra
possible. Modern communications make it possible to go far beyond that.
Consider listening in on cell phones, or intercepting electronic mail, or
tapping into the huge volumes of data on new media such as fiber optics or
satellite links. None of these targets existed in 1950. All of them can be
attacked today, and almost certainly are being attacked.</p>
<p>The Ultra story was not made public until the 1970s. Much of the recent
history of codes and code-breaking has not been made public, and some of it
may never be. Two important books are:</p>
<ul>
<li>Bamford's <a href="biblio.html#puzzle">The Puzzle Palace</a>, a history
of the NSA</li>
<li>Hager's <a href="http://www.fas.org/irp/eprint/sp/index.html">Secret
Power</a>, about the <a
href="http://sg.yahoo.com/government/intelligence/echelon_network/">Echelon</a>
system -- the US, UK, Canada, Australia and New Zealand co-operating to
monitor much of the world's communications.</li>
</ul>
<p>Note that these books cover only part of what is actually going on, and
then only the activities of nations open and democratic enough that (some of)
what they are doing can be discovered. A full picture, including:</p>
<ul>
<li>actions of the English-speaking democracies not covered in those
books</li>
<li>actions of other more-or-less sane governments</li>
<li>the activities of various more-or-less insane governments</li>
<li>possibilities for unauthorized action by government employees</li>
<li>possible actions by large non-government organisations: corporations,
criminals, or conspiracies</li>
</ul>
<p>might be really frightening.</p>
<h4><a name="recent">Recent history -- the crypto wars</a></h4>
<p>Until quite recently, cryptography was primarily a concern of governments,
especially of the military, of spies, and of diplomats. Much of it was
extremely secret.</p>
<p>In recent years, that has changed a great deal. With computers and
networking becoming ubiquitous, cryptography is now important to almost
everyone. Among the developments since the 1970s:</p>
<ul>
<li>The US gov't established the Data Encryption Standard, <a
href="glossary.html#DES">DES</a>, a <a href="glossary.html#block">block
cipher</a> for cryptographic protection of unclassfied documents.</li>
<li>DES also became widely used in industry, especially regulated
industries such as banking.</li>
<li>Other nations produced their own standards, such as <a
href="glossary.html#GOST">GOST</a> in the Soviet Union.</li>
<li><a href="glossary.html#public">Public key</a> cryptography was invented
by Diffie and Hellman.</li>
<li>Academic conferences such as <a
href="http://www-cse.ucsd.edu/users/mihir/crypto2k.html">Crypto</a> and
<a
href="http://www.esat.kuleuven.ac.be/cosic/eurocrypt2000/">Eurocrypt</a>
began.</li>
<li>Several companies began offerring cryptographic products: <a
href="glossary.html#RSAco">RSA</a>, <a href="glossary.html#PGPI">PGP</a>,
the many vendors with <a href="glossary.html#PKI">PKI</a> products,
...</li>
<li>Cryptography appeared in other products: operating systems, word
processors, ...</li>
<li>Network protocols based on crypto were developed: <a
href="glossary.html#SSH">SSH</a>, <a href="glossary.html#SSL">SSL</a>, <a
href="glossary.html#IPsec">IPsec</a>, ...</li>
<li>Crytography came into widespread use to secure bank cards, terminals,
...</li>
<li>The US government replaced <a href="glossary.html#DES">DES</a> with the
much stronger Advanced Encryption Standard, <a
href="glossary.html#AES">AES</a></li>
</ul>
<p>This has led to a complex ongoing battle between various mainly government
groups wanting to control the spread of crypto and various others, notably
the computer industry and the <a
href="http://online.offshore.com.ai/security/">cypherpunk</a> crypto
advocates, wanting to encourage widespread use.</p>
<p>Steven Levy has written a fine history of much of this, called <a
href="biblio.html#crypto">Crypto: How the Code rebels Beat the Government --
Saving Privacy in the Digital Age</a>.</p>
<p>The FreeS/WAN project is to a large extent an outgrowth of cypherpunk
ideas. Our reasons for doing the project can be seen in these quotes from the
<a
href="http://www.eff.org/pub/Privacy/Crypto_misc/cypherpunk.manifesto">Cypherpunk
Manifesto</a>:</p>
<blockquote>
Privacy is necessary for an open society in the electronic age. ...
<p>We cannot expect governments, corporations, or other large, faceless
organizations to grant us privacy out of their beneficence. It is to their
advantage to speak of us, and we should expect that they will speak.
...</p>
<p>We must defend our own privacy if we expect to have any. ...</p>
<p>Cypherpunks write code. We know that someone has to write software to
defend privacy, and since we can't get privacy unless we all do, we're
going to write it. We publish our code so that our fellow Cypherpunks may
practice and play with it. Our code is free for all to use, worldwide. We
don't much care if you don't approve of the software we write. We know
that software can't be destroyed and that a widely dispersed system can't
be shut down.</p>
<p>Cypherpunks deplore regulations on cryptography, for encryption is
fundamentally a private act. ...</p>
<p>For privacy to be widespread it must be part of a social contract.
People must come and together deploy these systems for the common good.
...</p>
</blockquote>
<p>To quote project leader John Gilmore:</p>
<blockquote>
We are literally in a race between our ability to build and deploy
technology, and their ability to build and deploy laws and treaties.
Neither side is likely to back down or wise up until it has definitively
lost the race.</blockquote>
<p>If FreeS/WAN reaches its goal of making <a
href="intro.html#opp.intro">opportunistic encryption</a> widespread so that
secure communication can become the default for a large part of the net, we
will have struck a major blow.</p>
<h3><a name="intro.poli">Politics</a></h3>
<p>The political problem is that nearly all governments want to monitor their
enemies' communications, and some want to monitor their citizens. They may be
very interested in protecting some of their own communications, and often
some types of business communication, but not in having everyone able to
communicate securely. They therefore attempt to restrict availability of
strong cryptography as much as possible.</p>
<p>Things various governments have tried or are trying include:</p>
<ul>
<li>Echelon, a monitor-the-world project of the US, UK, NZ, Australian and
Canadian <a href="glossary.html#SIGINT">signals intelligence</a>
agencies. See this <a
href="http://sg.yahoo.com/government/intelligence/echelon_network/">collection</a>
of links and this <a
href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640682,00.html">story</a>
on the French Parliament's reaction.</li>
<li>Others governments may well have their own Echelon-like projects. To
quote the Dutch Minister of Defense, as reported in a German <a
href="http://www.heise.de/tp/english/inhalt/te/4729/1.html">magazine</a>:
<blockquote>
The government believes not only the governments associated with
Echelon are able to intercept communication systems, but that it is an
activity of the investigative authorities and intelligence services of
many countries with governments of different political
signature.</blockquote>
Even if they have nothing on the scale of Echelon, most intelligence
agencies and police forces certainly have some interception
capability.</li>
<li><a href="glossary.html#NSA">NSA</a> tapping of submarine communication
cables, described in <a
href="http://www.zdnet.com/zdnn/stories/news/0,4586,2764372,00.html">this
article</a></li>
<li>A proposal for international co-operation on <a
href="http://www.heise.de/tp/english/special/enfo/4306/1.html">Internet
surveillance</a>.</li>
<li>Alleged <a href="http://cryptome.org/nsa-sabotage.htm">sabotage</a> of
security products by the <a href="glossary.html#NSA">NSA</a> (the US
signals intelligence agency).</li>
<li>The German armed forces and some government departments will stop using
American software for fear of NSA "back doors", according to this <a
href="http://www.theregister.co.uk/content/4/17679.html">news
story</a>.</li>
<li>The British Regulation of Investigatory Powers bill. See this <a
href="http://www.fipr.org/rip/index.html">web page.</a> and perhaps this
<a
href="http://ars.userfriendly.org/cartoons/?id=20000806&mode=classic">cartoon</a>.</li>
<li>A Russian <a
href="http://www.eff.org/pub/Privacy/Foreign_and_local/Russia/russian_crypto_ban_english.edict">ban</a>
on cryptography</li>
<li>Chinese <a
href="http://www.eff.org/pub/Misc/Publications/Declan_McCullagh/www/global/china">controls</a>
on net use.</li>
<li>The FBI's carnivore system for covert searches of email. See this <a
href="http://www.zdnet.com/zdnn/stories/news/0,4586,2601502,00.html">news
coverage</a> and this <a
href="http://www.crypto.com/papers/carnivore-risks.html">risk
assessment</a>. The government had an external review of some aspects of
this system done. See this <a
href="http://www.crypto.com/papers/carnivore_report_comments.html">analysis</a>
of that review. Possible defenses against Carnivore include:
<ul>
<li><a href="glossary.html#PGP">PGP</a> for end-to-end mail
encryption</li>
<li><a href="http://www.home.aone.net.au/qualcomm/">secure sendmail</a>
for server-to-server encryption</li>
<li>IPsec encryption on the underlying IP network</li>
</ul>
</li>
<li>export laws restricting strong cryptography as a munition. See <a
href="#exlaw">discussion</a> below.</li>
<li>various attempts to convince people that fundamentally flawed
cryptography, such as encryption with a <a href="#escrow">back door</a>
for government access to data or with <a href="#shortkeys">inadequate key
lengths</a>, was adequate for their needs.</li>
</ul>
<p>Of course governments are by no means the only threat to privacy and
security on the net. Other threats include:</p>
<ul>
<li>industrial espionage, as for example in this <a
href="http://www.zdnet.com/zdnn/stories/news/0,4586,2626931,00.html">news
story</a></li>
<li>attacks by organised criminals, as in this <a
href="http://www.sans.org/newlook/alerts/NTE-bank.htm">large-scale
attack</a></li>
<li>collection of personal data by various companies.
<ul>
<li>for example, consider the various corporate winners of Privacy
International's <a
href="http://www.privacyinternational.org/bigbrother/">Big Brother
Awards</a>.</li>
<li><a href="http://www.zeroknowledge.com">Zero Knowledge</a> sell
tools to defend against this</li>
</ul>
</li>
<li>individuals may also be a threat in a variety of ways and for a variety
of reasons</li>
<li>in particular, an individual with access to government or industry data
collections could do considerable damage using that data in unauthorized
ways.</li>
</ul>
<p>One <a
href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640674,00.html">study</a>
enumerates threats and possible responses for small and medium businesses.
VPNs are a key part of the suggested strategy.</p>
<p>We consider privacy a human right. See the UN's <a href="http://www.un.org/Overview/rights.html">Universal
Declaration of Human Rights</a>, article twelve:</p>
<blockquote>
No one shall be subjected to arbitrary interference with his privacy,
family, home or correspondence, nor to attacks upon his honor and
reputation. Everyone has the right to the protection of the law against
such interference or attacks.</blockquote>
<p>Our objective is to help make privacy possible on the Internet using
cryptography strong enough not even those well-funded government agencies are
likely to break it. If we can do that, the chances of anyone else breaking it
are negliible.</p>
<h3>Links</h3>
<p>Many groups are working in different ways to defend privacy on the net and
elsewhere. Please consider contributing to one or more of these groups:</p>
<ul>
<li>the EFF's <a href="http://www.eff.org/crypto/">Privacy Now!</a>
campaign</li>
<li>the <a href="http://www.gilc.org">Global Internet Liberty
Campaign</a></li>
<li><a href="http://www.cpsr.org/program/privacy/privacy.html">Computer
Professionals for Social Responsibility</a></li>
</ul>
<p>For more on these issues see:</p>
<ul>
<li>Steven Levy (Newsweek's chief technology writer and author of the
classic "Hackers") new book <a href="biblio.html#crypto">Crypto: How the
Code Rebels Beat the Government--Saving Privacy in the Digital
Age</a></li>
<li>Simson Garfinkel (Boston Globe columnist and author of books on <a
href="biblio.html#PGP">PGP</a> and <a href="biblio.html#practical">Unix
Security</a>) book <a href="biblio.html#Garfinkel">Database Nation: the
death of privacy in the 21st century</a></li>
</ul>
<p>There are several collections of <a href="web.html#quotes">crypto
quotes</a> on the net.</p>
<p>See also the <a href="biblio.html">bibliography</a> and our list of <a
href="web.html#policy">web references</a> on cryptography law and policy.</p>
<h3>Outline of this section</h3>
<p>The remainder of this section includes two pieces of writing by our
project leader</p>
<ul>
<li>his <a href="#gilmore">rationale</a> for starting this</li>
<li>another <a href="#policestate">discussion</a> of project goals</li>
</ul>
<p>and discussions of:</p>
<ul>
<li><a href="#desnotsecure">why we do not use DES</a></li>
<li><a href="#exlaw">cryptography export laws</a></li>
<li>why <a href="#escrow">government access to keys</a> is not a good
idea</li>
<li>the myth that <a href="#shortkeys">short keys</a> are adequate for some
security requirements</li>
</ul>
<p>and a section on <a href="#press">press coverage of FreeS/WAN</a>.</p>
<h2><a name="leader">From our project leader</a></h2>
<p>FreeS/WAN project founder John Gilmore wrote a web page about why we are
doing this. The version below is slightly edited, to fit this format and to
update some links. For a version without these edits, see his <a
href="http://www.toad.com/gnu/">home page</a>.</p>
<center>
<h3><a name="gilmore">Swan: Securing the Internet against Wiretapping</a></h3>
</center>
<p>My project for 1996 was to <b>secure 5% of the Internet traffic against
passive wiretapping</b>. It didn't happen in 1996, so I'm still working on it
in 1997, 1998, and 1999! If we get 5% in 1999 or 2000, we can secure 20% the
next year, against both active and passive attacks; and 80% the following
year. Soon the whole Internet will be private and secure. The project is
called S/WAN or S/Wan or Swan for Secure Wide Area Network; since it's free
software, we call it FreeSwan to distinguish it from various commercial
implementations. <a href="http://www.rsa.com/rsa/SWAN/">RSA</a> came up with
the term "S/WAN". Our main web site is at <a
href="http://www.freeswan.org/">http://www.freeswan.org/</a>. Want to
help?</p>
<p>The idea is to deploy PC-based boxes that will sit between your local area
network and the Internet (near your firewall or router) which
opportunistically encrypt your Internet packets. Whenever you talk to a
machine (like a Web site) that doesn't support encryption, your traffic goes
out "in the clear" as usual. Whenever you connect to a machine that does
support this kind of encryption, this box automatically encrypts all your
packets, and decrypts the ones that come in. In effect, each packet gets put
into an "envelope" on one side of the net, and removed from the envelope when
it reaches its destination. This works for all kinds of Internet traffic,
including Web access, Telnet, FTP, email, IRC, Usenet, etc.</p>
<p>The encryption boxes are standard PC's that use freely available Linux
software that you can download over the Internet or install from a cheap
CDROM.</p>
<p>This wasn't just my idea; lots of people have been working on it for
years. The encryption protocols for these boxes are called <a
href="glossary.html#IPsec">IPSEC (IP Security)</a>. They have been developed
by the <a
href="http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html">IP
Security Working Group</a> of the <a href="http://www.ietf.org/">Internet
Engineering Task Force</a>, and will be a standard part of the next major
version of the Internet protocols (<a
href="http://playground.sun.com/pub/ipng/html/ipng-main.html">IPv6</a>). For
today's (IP version 4) Internet, they are an option.</p>
<p>The <a href="http://www.iab.org/iab">Internet Architecture Board</a> and
<a href="http://www.ietf.org/">Internet Engineering Steering Group</a> have
taken a <a href="iab-iesg.stmt">strong stand</a> that the Internet should use
powerful encryption to provide security and privacy. I think these protocols
are the best chance to do that, because they can be deployed very easily,
without changing your hardware or software or retraining your users. They
offer the best security we know how to build, using the Triple-DES, RSA, and
Diffie-Hellman algorithms.</p>
<p>This "opportunistic encryption box" offers the "fax effect". As each
person installs one for their own use, it becomes more valuable for their
neighbors to install one too, because there's one more person to use it with.
The software automatically notices each newly installed box, and doesn't
require a network administrator to reconfigure it. Instead of "virtual
private networks" we have a "REAL private network"; we add privacy to the
real network instead of layering a manually-maintained virtual network on top
of an insecure Internet.</p>
<h4>Deployment of IPSEC</h4>
<p>The US government would like to control the deployment of IP Security with
its <a href="#exlaw">crypto export laws</a>. This isn't a problem for my
effort, because the cryptographic work is happening outside the United
States. A foreign philanthropist, and others, have donated the resources
required to add these protocols to the Linux operating system. <a
href="http://www.linux.org/">Linux</a> is a complete, freely available
operating system for IBM PC's and several kinds of workstation, which is
compatible with Unix. It was written by Linus Torvalds, and is still
maintained by a talented team of expert programmers working all over the
world and coordinating over the Internet. Linux is distributed under the <a
href="glossary.html#GPL">GNU Public License</a>, which gives everyone the
right to copy it, improve it, give it to their friends, sell it commercially,
or do just about anything else with it, without paying anyone for the
privilege.</p>
<p>Organizations that want to secure their network will be able to put two
Ethernet cards into an IBM PC, install Linux on it from a $30 CDROM or by
downloading it over the net, and plug it in between their Ethernet and their
Internet link or firewall. That's all they'll have to do to encrypt their
Internet traffic everywhere outside their own local area network.</p>
<p>Travelers will be able to run Linux on their laptops, to secure their
connection back to their home network (and to everywhere else that they
connect to, such as customer sites). Anyone who runs Linux on a standalone PC
will also be able to secure their network connections, without changing their
application software or how they operate their computer from day to day.</p>
<p>There will also be numerous commercially available firewalls that use this
technology. <a href="http://www.rsa.com/">RSA Data Security</a> is
coordinating the <a href="http://www.rsa.com/rsa/SWAN">S/Wan (Secure Wide
Area Network)</a> project among more than a dozen vendors who use these
protocols. There's a <a
href="http://www.rsa.com/rsa/SWAN/swan_test.htm">compatability chart</a> that
shows which vendors have tested their boxes against which other vendors to
guarantee interoperatility.</p>
<p>Eventually it will also move into the operating systems and networking
protocol stacks of major vendors. This will probably take longer, because
those vendors will have to figure out what they want to do about the export
controls.</p>
<h4>Current status</h4>
<p>My initial goal of securing 5% of the net by Christmas '96 was not met. It
was an ambitious goal, and inspired me and others to work hard, but was
ultimately too ambitious. The protocols were in an early stage of
development, and needed a lot more protocol design before they could be
implemented. As of April 1999, we have released version 1.0 of the software
(<a
href="ftp://ftp.xs4all.nl/freeswan/freeswan-1.0.tar.gz">freeswan-1.0.tar.gz</a>),
which is suitable for setting up Virtual Private Networks using shared
secrets for authentication. It does not yet do opportunistic encryption, or
use DNSSEC for authentication; those features are coming in a future
release.</p>
<dl>
<dt>Protocols</dt>
<dd>The low-level encrypted packet formats are defined. The system for
publishing keys and providing secure domain name service is defined.
The IP Security working group has settled on an NSA-sponsored protocol
for key agreement (called ISAKMP/Oakley), but it is still being worked
on, as the protocol and its documentation is too complex and
incomplete. There are prototype implementations of ISAKMP. The
protocol is not yet defined to enable opportunistic encryption or the
use of DNSSEC keys.</dd>
<dt>Linux Implementation</dt>
<dd>The Linux implementation has reached its first major release and is
ready for production use in manually-configured networks, using Linux
kernel version 2.0.36.</dd>
<dt>Domain Name System Security</dt>
<dd>There is now a release of BIND 8.2 that includes most DNS Security
features.
<p>The first prototype implementation of Domain Name System Security
was funded by <a href="glossary.html#DARPA">DARPA</a> as part of their
<a href="http://www.darpa.mil/ito/research/is/index.html">Information
Survivability program</a>. <a href="http://www.tis.com">Trusted
Information Systems</a> wrote a modified version of <a
href="http://www.isc.org/bind.html">BIND</a>, the widely-used Berkeley
implementation of the Domain Name System.</p>
<p>TIS, ISC, and I merged the prototype into the standard version of
BIND. The first production version that supports KEY and SIG records is
<b>bind-4.9.5</b>. This or any later version of BIND will do for
publishing keys. It is available from the <a
href="http://www.isc.org/bind.html">Internet Software Consortium</a>.
This version of BIND is not export-controlled since it does not contain
any cryptography. Later releases starting with BIND 8.2 include
cryptography for authenticating DNS records, which is also exportable.
Better documentation is needed.</p>
</dd>
</dl>
<h4>Why?</h4>
<p>Because I can. I have made enough money from several successful startup
companies, that for a while I don't have to work to support myself. I spend
my energies and money creating the kind of world that I'd like to live in and
that I'd like my (future) kids to live in. Keeping and improving on the civil
rights we have in the United States, as we move more of our lives into
cyberspace, is a particular goal of mine.</p>
<h4>What You Can Do</h4>
<dl>
<dt>Install the latest BIND at your site.</dt>
<dd>You won't be able to publish any keys for your domain, until you have
upgraded your copy of BIND. The thing you really need from it is the
new version of <i>named</i>, the Name Daemon, which knows about the new
KEY and SIG record types. So, download it from the <a
href="http://www.isc.org/bind.html">Internet Software Consortium </a>
and install it on your name server machine (or get your system
administrator, or Internet Service Provider, to install it). Both your
primary DNS site and all of your secondary DNS sites will need the new
release before you will be able to publish your keys. You can tell
which sites this is by running the Unix command "dig MYDOMAIN ns" and
seeing which sites are mentioned in your NS (name server) records.</dd>
<dt>Set up a Linux system and run a 2.0.x kernel on it</dt>
<dd>Get a machine running Linux (say the 5.2 release from <a
href="http://www.redhat.com">Red Hat</a>). Give the machine two
Ethernet cards.</dd>
<dt>Install the Linux IPSEC (Freeswan) software</dt>
<dd>If you're an experienced sysadmin or Linux hacker, install the
freeswan-1.0 release, or any later release or snapshot. These releases
do NOT provide automated "opportunistic" operation; they must be
manually configured for each site you wish to encrypt with.</dd>
<dt>Get on the linux-ipsec mailing list</dt>
<dd>The discussion forum for people working on the project, and testing
the code and documentation, is: linux-ipsec@clinet.fi. To join this
mailing list, send email to <a
href="mailto:linux-ipsec-REQUEST@clinet.fi">linux-ipsec-REQUEST@clinet.fi</a>
containing a line of text that says "subscribe linux-ipsec". (You can
later get off the mailing list the same way -- just send "unsubscribe
linux-ipsec").</dd>
<p></p>
<dt>Check back at this web page every once in a while</dt>
<dd>I update this page periodically, and there may be new information in
it that you haven't seen. My intent is to send email to the mailing
list when I update the page in any significant way, so subscribing to
the list is an alternative.</dd>
</dl>
<p>Would you like to help? I can use people who are willing to write
documentation, install early releases for testing, write cryptographic code
outside the United States, sell pre-packaged software or systems including
this technology, and teach classes for network administrators who want to
install this technology. To offer to help, send me email at gnu@toad.com.
Tell me what country you live in and what your citizenship is (it matters due
to the export control laws; personally I don't care). Include a copy of your
resume and the URL of your home page. Describe what you'd like to do for the
project, and what you're uniquely qualified for. Mention what other
volunteer projects you've been involved in (and how they worked out). Helping
out will require that you be able to commit to doing particular things, meet
your commitments, and be responsive by email. Volunteer projects just don't
work without those things.</p>
<h4>Related projects</h4>
<dl>
<dt>IPSEC for NetBSD</dt>
<dd>This prototype implementation of the IP Security protocols is for
another free operating system. <a
href="ftp://ftp.funet.fi/pub/unix/security/net/ip/BSDipsec.tar.gz">Download
BSDipsec.tar.gz</a>.</dd>
<dt>IPSEC for <a href="http://www.openbsd.org">OpenBSD</a></dt>
<dd>This prototype implementation of the IP Security protocols is for yet
another free operating system. It is directly integrated into the OS
release, since the OS is maintained in Canada, which has freedom of
speech in software.</dd>
</dl>
<h3><a name="policestate">Stopping wholesale monitoring</a></h3>
<p>From a message project leader John Gilmore posted to the mailing list:</p>
<pre>John Denker wrote:
> Indeed there are several ways in which the documentation overstates the
> scope of what this project does -- starting with the name
> FreeS/WAN. There's a big difference between having an encrypted IP tunnel
> versus having a Secure Wide-Area Network. This software does a fine job of
> the former, which is necessary but not sufficient for the latter.
The goal of the project is to make it very hard to tap your wide area
communications. The current system provides very good protection
against passive attacks (wiretapping and those big antenna farms).
Active attacks, which involve the intruder sending packets to your
system (like packets that break into sendmail and give them a root
shell :-) are much harder to guard against. Active attacks that
involve sending people (breaking into your house and replacing parts
of your computer with ones that transmit what you're doing) are also
much harder to guard against. Though we are putting effort into
protecting against active attacks, it's a much bigger job than merely
providing strong encryption. It involves general computer security,
and general physical security, which are two very expensive problems
for even a site to solve, let alone to build into a whole society.
The societal benefit of building an infrastructure that protects
well against passive attacks is that it makes it much harder to do
undetected bulk monitoring of the population. It's a defense against
police-states, not against policemen.
Policemen can put in the effort required to actively attack sites that
they have strong suspicions about. But police states won't be able to
build systems that automatically monitor everyone's communications.
Either they will be able to monitor only a small subset of the
populace (by targeting those who screwed up their passive security),
or their monitoring activities will be detectable by those monitored
(active attacks leave packet traces or footprints), which can then be
addressed through the press and through political means if they become
too widespread.
FreeS/WAN does not protect very well against traffic analysis, which
is a kind of widespread police-state style monitoring that still
reveals significant information (who's talking to who) without
revealing the contents of what was said. Defenses against traffic
analysis are an open research problem. Zero Knowledge Systems is
actively deploying a system designed to thwart it, designed by Ian
Goldberg. The jury is out on whether it actually works; a lot more
experience with it will be needed.</pre>
<p>Notes on things mentioned in that message:</p>
<ul>
<li>Denker is a co-author of a <a href="intro.html#applied">paper</a> on a
large FreeS/WAN application.</li>
<li>Information on Zero Knowledge is on their <a
href="http://www.zks.net/">web site</a>. Their Freedom product, designed
to provide untracable pseudonyms for use on the net, is no longer
marketed.</li>
<li>Another section of our documentation discusses ways to <a
href="ipsec.html#traffic.resist">resist traffic analysis</a>.</li>
</ul>
<h2><a name="weak">Government promotion of weak crypto</a></h2>
<p>Various groups, especially governments and especially the US government,
have a long history of advocating various forms of bogus security.</p>
<p>We regard bogus security as extremely dangerous. If users are deceived
into relying on bogus security, then they may be exposed to large risks. They
would be better off having no security and knowing it. At least then they
would be careful about what they said.</p>
<p><strong>Avoiding bogus security is a key design criterion for everything
we do in FreeS/WAN</strong>. The most conspicuous example is our refusal to
support <a href="#desnotsecure">single DES</a>. Other IPsec "features" which
we do not implement are discussed in our <a
href="compat.html#dropped">compatibility</a> document.</p>
<h3><a name="escrow">Escrowed encryption</a></h3>
<p>Various governments have made persistent attempts to encourage or mandate
"escrowed encrytion", also called "key recovery", or GAK for "government
access to keys". The idea is that cryptographic keys be held by some third
party and turned over to law enforcement or security agencies under some
conditions.</p>
<pre> Mary had a little key - she kept it in escrow,
and every thing that Mary said,
the feds were sure to know.</pre>
<p>A <a href="web.html#quotes">crypto quotes</a> page attributes this to <a
href="http://www.scramdisk.clara.net/">Sam Simpson</a>.</p>
<p>There is an excellent paper available on <a
href="http://www.cdt.org/crypto/risks98/">Risks of Escrowed Encryption</a>,
from a group of cryptographic luminaries which included our project
leader.</p>
<p>Like any unnecessary complication, GAK tends to weaken security of any
design it infects. For example:</p>
<ul>
<li>Matt Blaze found a fatal flaw in the US government's Clipper chip
shortly after design information became public. See his paper "Protocol
Failure in the Escrowed Encryption Standard" on his <a
href="http://www.crypto.com/papers/">papers</a> page.</li>
<li>a rather <a href="http://www.pgp.com/other/advisories/adk.asp">nasty
bug</a> was found in the "additional decryption keys" "feature" of some
releases of <a href="glossary.html#PGP">PGP</a></li>
</ul>
<p>FreeS/WAN does not support escrowed encryption, and never will.</p>
<h3><a name="shortkeys">Limited key lengths</a></h3>
<p>Various governments, and some vendors, have also made persistent attempts
to convince people that:</p>
<ul>
<li>weak systems are sufficient for some data</li>
<li>strong cryptography should be reserved for cases where the extra
overheads are justified</li>
</ul>
<p><strong>This is utter nonsense</strong>.</p>
<p>Weak systems touted include:</p>
<ul>
<li>the ludicrously weak (deliberately crippled) 40-bit ciphers that until
recently were all various <a href="#exlaw">export laws</a> allowed</li>
<li>56-bit single DES, discussed <a href="#desnotsecure">below</a></li>
<li>64-bit symmetric ciphers and 512-bit RSA, the maximums for unrestricted
export under various current laws</li>
</ul>
<p>The notion that choice of ciphers or keysize should be determined by a
trade-off between security requirements and overheads is pure bafflegab.</p>
<ul>
<li>For most <a href="glossary.html#symmetric">symmetric ciphers</a>, it is
simply a lie. Any block cipher has some natural maximum keysize inherent
in the design -- 128 bits for <a href="glossary.html#IDEA">IDEA</a> or <a
href="glossary.html#CAST128">CAST-128</a>, 256 for Serpent or Twofish,
448 for <a href="glossary.html#Blowfish">Blowfish</a> and 2048 for <a
href="glossary.html#RC4">RC4</a>. Using a key size smaller than that
limit gives <em>exactly zero </em>savings in overhead. The crippled
40-bit or 64-bit version of the cipher provides <em>no advantage
whatsoever</em>.</li>
<li><a href="glossary.html#AES">AES</a> uses 10 rounds with 128-bit keys,
12 rounds for 192-bit and 14 rounds for 256-bit, so there actually is a
small difference in overhead, but not enough to matter in most
applications.</li>
<li>For <a href="glossary.html#3DES">triple DES</a> there is a grain of
truth in the argument. 3DES is indeed three times slower than single DES.
However, the solution is not to use the insecure single DES, but to pick
a faster secure cipher. <a href="glossary.html#CAST128">CAST-128</a>, <a
href="glossary.html#Blowfish">Blowfish</a> and the <a
href="glossary.html#AES">AES candidate</a> ciphers are are all
considerably faster in software than DES (let alone 3DES!), and
apparently secure.</li>
<li>For <a href="glossary.html#public">public key</a> techniques, there are
extra overheads for larger keys, but they generally do not affect overall
performance significantly. Practical public key applications are usually
<a href="glossary.html#hybrid">hybrid</a> systems in which the bulk of
the work is done by a symmetric cipher. The effect of increasing the cost
of the public key operations is typically negligible because the public
key operations use only a tiny fraction of total resources.
<p>For example, suppose public key operations use use 1% of the time in a
hybrid system and you triple the cost of public key operations. The cost
of symmetric cipher operations is unchanged at 99% of the original total
cost, so the overall effect is a jump from 99 + 1 = 100 to 99 + 3 = 102,
a 2% rise in system cost.</p>
</li>
</ul>
<p>In short, <strong>there has never been any technical reason to use
inadequate ciphers</strong>. The only reason there has ever been for anyone
to use such ciphers is that government agencies want weak ciphers used so
that they can crack them. The alleged savings are simply propaganda.</p>
<pre> Mary had a little key (It's all she could export),
and all the email that she sent was opened at the Fort.</pre>
<p>A <a href="web.html#quotes">crypto quotes</a> page attributes this to <a
href="http://theory.lcs.mit.edu:80/~rivest/">Ron Rivest</a>. NSA headquarters
is at Fort Meade, Maryland.</p>
<p>Our policy in FreeS/WAN is to use only cryptographic components with
adequate keylength and no known weaknesses.</p>
<ul>
<li>We do not implement single DES because it is clearly <a
href="#desnotsecure">insecure</a>, so implemeting it would violate our
policy of avoiding bogus security. Our default cipher is <a
href="glossary.html#3DES">3DES</a></li>
<li>Similarly, we do not implement the 768-bit Group 1 for <a
href="glossary.html#DH">Diffie-Hellman</a> key negotiation. We provide
only the 1024-bit Group 2 and 1536-bit Group 5.</li>
</ul>
<p>Detailed discussion of which IPsec features we implement or omit is in out
<a href="compat.html">compatibility document</a>.</p>
<p>These decisions imply that we cannot fully conform to the IPsec RFCs,
since those have DES as the only required cipher and Group 1 as the only
required DH group. (In our view, the standards were subverted into offerring
bogus security.) Fortunately, we can still interoperate with most other IPsec
implementations since nearly all implementers provide at least 3DES and Group
2 as well.</p>
<p>We hope that eventually the RFCs will catch up with our (and others')
current practice and reject dubious components. Some of our team and a number
of others are working on this in <a href="glossary.html#IETF">IETF</a>
working groups.</p>
<h4>Some real trade-offs</h4>
<p>Of course, making systems secure does involve costs, and trade-offs can be
made between cost and security. However, the real trade-offs have nothing to
do with using weaker ciphers.</p>
<p>There can be substantial hardware and software costs. There are often
substantial training costs, both to train administrators and to increase user
awareness of security issues and procedures. There are almost always
substantial staff or contracting costs.</p>
<p>Security takes staff time for planning, implementation, testing and
auditing. Some of the issues are subtle; you need good (hence often
expensive) people for this. You also need people to monitor your systems and
respond to problems. The best safe ever built is insecure if an attacker can
work on it for days without anyone noticing. Any computer is insecure if the
administrator is "too busy" to check the logs.</p>
<p>Moreover, someone in your organisation (or on contract to it) needs to
spend considerable time keeping up with new developments. EvilDoers
<em>will</em> know about new attacks shortly after they are found. You need
to know about them before your systems are attacked. If your vendor provides
a patch, you need to apply it. If the vendor does nothing, you need to
complain or start looking for another vendor.</p>
<p>For a fairly awful example, see this <a
href="http://www.sans.org/newlook/alerts/NTE-bank.htm">report</a>. In that
case over a million credit card numbers were taken from e-commerce sites,
using security flaws in Windows NT servers. Microsoft had long since released
patches for most or all of the flaws, but the site administrators had not
applied them.</p>
<p>At an absolute minimum, you must do something about such issues
<em>before</em> an exploitation tool is posted to the net for downloading by
dozens of "script kiddies". Such a tool might appear at any time from the
announcement of the security hole to several months later. Once it appears,
anyone with a browser and an attitude can break any system whose
administrators have done nothing about the flaw.</p>
<p>Compared to those costs, cipher overheads are an insignificant factor in
the cost of security.</p>
<p>The only thing using a weak cipher can do for you is to cause all your
other investment to be wasted.</p>
<h2><a name="exlaw">Cryptography Export Laws</a></h2>
<p>Many nations restrict the export of cryptography and some restrict its use
by their citizens or others within their borders.</p>
<h3><a name="USlaw">US Law</a></h3>
<p>US laws, as currently interpreted by the US government, forbid export of
most cryptographic software from the US in machine-readable form without
government permission. In general, the restrictions apply even if the
software is widely-disseminated or public-domain and even if it came from
outside the US originally. Cryptography is legally a munition and export is
tightly controlled under the <a href="glossary.html#EAR">EAR</a> Export
Administration Regulations.</p>
<p>If you are a US citizen, your brain is considered US territory no matter
where it is physically located at the moment. The US believes that its laws
apply to its citizens everywhere, not just within the US. Providing technical
assistance or advice to foreign "munitions" projects is illegal. The US
government has very little sense of humor about this issue and does not
consider good intentions to be sufficient excuse. Beware.</p>
<p>The <a href="http://www.bxa.doc.gov/Encryption/">official website</a> for
these regulations is run by the Commerce Department's Bureau of Export
Administration (BXA).</p>
<p>The <a href="http://www.eff.org/bernstein/">Bernstein case</a> challenges
the export restrictions on Constitutional grounds. Code is speech so
restrictions on export of code violate the First Amendment's free speech
provisions. This argument has succeeded in two levels of court so far. It is
quite likely to go on to the Supreme Court.</p>
<p>The regulations were changed substantially in January 2000, apparently as
a government attempt to get off the hook in the Bernstein case. It is now
legal to export public domain source code for encryption, provided you notify
the <a href="glossary.html#BXA">BXA</a>.</p>
<p>There are, however, still restrictions in force.
Moreover, the regulations can still be changed again whenever the government
chooses to do so. Short of a Supreme Court ruling (in the Berstein case or
another) that overturns the regulations completely, the problem of export
regulation is not likely to go away in the forseeable future.</p>
<h4><a name="UScontrib">US contributions to FreeS/WAN</a></h4>
<p>The FreeS/WAN project <strong>cannot accept software contributions, <em>
not even small bug fixes</em>, from US citizens or residents</strong>. We
want it to be absolutely clear that our distribution is not subject to US
export law. Any contribution from an American might open that question to a
debate we'd prefer to avoid. It might also put the contributor at serious
legal risk.</p>
<p>Of course Americans can still make valuable contributions (many already
have) by reporting bugs, or otherwise contributing to discussions, on the
project <a href="mail.html">mailing list</a>. Since the list is public, this
is clearly constitutionally protected free speech.</p>
<p>Note, however, that the export laws restrict Americans from providing
technical assistance to foreign "munitions" projects. The government might
claim that private discussions or correspondence with FreeS/WAN developers
were covered by this. It is not clear what the courts would do with such a
claim, so we strongly encourage Americans to use the list rather than risk
the complications.</p>
<h3><a name="wrong">What's wrong with restrictions on cryptography</a></h3>
<p>Some quotes from prominent cryptography experts:</p>
<blockquote>
The real aim of current policy is to ensure the continued effectiveness of
US information warfare assets against individuals, businesses and
governments in Europe and elsewhere.<br>
<a href="http://www.cl.cam.ac.uk/users/rja14"> Ross Anderson, Cambridge
University</a></blockquote>
<blockquote>
If the government were honest about its motives, then the debate about
crypto export policy would have ended years ago.<br>
<a href="http://www.counterpane.com"> Bruce Schneier, Counterpane
Systems</a></blockquote>
<blockquote>
The NSA regularly lies to people who ask it for advice on export control.
They have no reason not to; accomplishing their goal by any legal means is
fine by them. Lying by government employees is legal.<br>
John Gilmore.</blockquote>
<p>The Internet Architecture Board (IAB) and the Internet Engineering
Steering Group (IESG) made a <a href="iab-iesg.stmt">strong statement</a> in
favour of worldwide access to strong cryptography. Essentially the same
statement is in the appropriately numbered <a
href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">RFC 1984</a>. Two critical
paragraphs are:</p>
<blockquote>
... various governments have actual or proposed policies on access to
cryptographic technology ...
<p>(a) ... export controls ...<br>
(b) ... short cryptographic keys ...<br>
(c) ... keys should be in the hands of the government or ...<br>
(d) prohibit the use of cryptology ...</p>
<p>We believe that such policies are against the interests of consumers and
the business community, are largely irrelevant to issues of military
security, and provide only a marginal or illusory benefit to law
enforcement agencies, ...</p>
<p>The IAB and IESG would like to encourage policies that allow ready
access to uniform strong cryptographic technology for all Internet users in
all countries.</p>
</blockquote>
<p>Our goal in the FreeS/WAN project is to build just such "strong
cryptographic technology" and to distribute it "for all Internet users in all
countries".</p>
<p>More recently, the same two bodies (IESG and IAB) have issued <a
href="ftp://ftp.isi.edu/in-notes/rfc2804.txt">RFC 2804</a> on why the IETF
should not build wiretapping capabilities into protocols for the convenience
of security or law enforcement agenicies. The abstract from that document
is:</p>
<blockquote>
The Internet Engineering Task Force (IETF) has been asked to take a
position on the inclusion into IETF standards-track documents of
functionality designed to facilitate wiretapping.
<p>This memo explains what the IETF thinks the question means, why its
answer is "no", and what that answer means.</p>
</blockquote>
A quote from the debate leading up to that RFC:
<blockquote>
We should not be building surveillance technology into standards. Law
enforcement was not supposed to be easy. Where it is easy, it's called a
police state.<br>
Jeff Schiller of MIT, in a discussion of FBI demands for wiretap capability
on the net, as quoted by <a
href="http://www.wired.com/news/politics/0,1283,31895,00.html">Wired</a>.</blockquote>
<p>The <a href="http://www.ietf.org/mailman/listinfo/raven">Raven</a> mailing
list was set up for this IETF discussion.</p>
<p>Our goal is to go beyond that RFC and prevent Internet wiretapping
entirely.</p>
<h3><a name="Wassenaar">The Wassenaar Arrangement</a></h3>
<p>Restrictions on the export of cryptography are not just US policy, though
some consider the US at least partly to blame for the policies of other
nations in this area.</p>
<p>A number of countries:</p>
<p>Argentina, Australia, Austria, Belgium, Bulgaria, Canada, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan,
Luxembourg, Netherlands, New Zealand, Norway, Poland, Portugal, Republic of
Korea, Romania, Russian Federation, Slovak Republic, Spain, Sweden,
Switzerland, Turkey, Ukraine, United Kingdom and United States</p>
<p>have signed the Wassenaar Arrangement which restricts export of munitions
and other tools of war. Cryptographic sofware is covered there.</p>
<p>Wassenaar details are available from the <a
href="http://www.wassenaar.org/"> Wassenaar Secretariat</a>, and elsewhere in
a more readable <a href="http://www.fitug.de/news/wa/index.html"> HTML
version</a>.</p>
<p>For a critique see the <a href="http://www.gilc.org/crypto/wassenaar">
GILC site</a>:</p>
<blockquote>
The Global Internet Liberty Campaign (GILC) has begun a campaign calling
for the removal of cryptography controls from the Wassenaar Arrangement.
<p>The aim of the Wassenaar Arrangement is to prevent the build up of
military capabilities that threaten regional and international security and
stability . . .</p>
<p>There is no sound basis within the Wassenaar Arrangement for the
continuation of any export controls on cryptographic products.</p>
</blockquote>
<p>We agree entirely.</p>
<p>An interesting analysis of Wassenaar can be found on the <a
href="http://www.cyber-rights.org/crypto/wassenaar.htm">cyber-rights.org</a>
site.</p>
<h3><a name="status">Export status of Linux FreeS/WAN</a></h3>
<p>We believe our software is entirely exempt from these controls since the
Wassenaar <a
href="http://www.wassenaar.org/list/GTN%20and%20GSN%20-%2099.pdf">General
Software Note</a> says:</p>
<blockquote>
The Lists do not control "software" which is either:
<ol>
<li>Generally available to the public by . . . retail . . . or</li>
<li>"In the public domain".</li>
</ol>
</blockquote>
<p>There is a note restricting some of this, but it is a sub-heading under
point 1, so it appears not to apply to public domain software.</p>
<p>Their glossary defines "In the public domain" as:</p>
<blockquote>
. . . "technology" or "software" which has been made available without
restrictions upon its further dissemination.
<p>N.B. Copyright restrictions do not remove "technology" or "software"
from being "in the public domain".</p>
</blockquote>
<p>We therefore believe that software freely distributed under the <a
href="glossary.html#GPL">GNU Public License</a>, such as Linux FreeS/WAN, is
exempt from Wassenaar restrictions.</p>
<p>Most of the development work is being done in Canada. Our understanding is
that the Canadian government accepts this interpretation.</p>
<ul>
<li>A web statement of <a
href="http://www.dfait-maeci.gc.ca/~eicb/notices/ser113-e.htm"> Canadian
policy</a> is available from the Department of Foreign Affairs and
International Trade.</li>
<li>Another document from that department states that <a
href="http://www.dfait-maeci.gc.ca/~eicb/export/gr1_e.htm">public domain
software</a> is exempt from the export controls.</li>
<li>A researcher's <a
href="http://insight.mcmaster.ca/org/efc/pages/doc/crypto-export.html">analysis</a>
of Canadian policy is also available.</li>
</ul>
<p>Recent copies of the freely modifiable and distributable source code exist
in many countries. Citizens all over the world participate in its use and
evolution, and guard its ongoing distribution. Even if Canadian policy were
to change, the software would continue to evolve in countries which do not
restrict exports, and would continue to be imported from there into unfree
countries. "The Net culture treats censorship as damage, and routes around
it."</p>
<h3><a name="help">Help spread IPsec around</a></h3>
<p>You can help. If you don't know of a Linux FreeS/WAN archive in your own
country, please download it now to your personal machine, and consider making
it publicly accessible if that doesn't violate your own laws. If you have the
resources, consider going one step further and setting up a mirror site for
the whole <a href="intro.html#munitions">munitions</a> Linux crypto software
archive.</p>
<p>If you make Linux CD-ROMs, please consider including this code, in a way
that violates no laws (in a free country, or in a domestic-only CD
product).</p>
<p>Please send a note about any new archive mirror sites or CD distributions
to linux-ipsec@clinet.fi so we can update the documentation.</p>
<p>Lists of current <a href="intro.html#sites">mirror sites</a> and of <a
href="intro.html#distwith">distributions</a> which include FreeS/WAN are in
our introduction section.</p>
<h2><a name="desnotsecure">DES is Not Secure</a></h2>
<p>DES, the <strong>D</strong>ata <strong>E</strong>ncryption
<strong>S</strong>tandard, can no longer be considered secure. While no major
flaws in its innards are known, it is fundamentally inadequate because its
<strong>56-bit key is too short</strong>. It is vulnerable to <a
href="glossary.html#brute">brute-force search</a> of the whole key space,
either by large collections of general-purpose machines or even more quickly
by specialized hardware. Of course this also applies to <strong>any other
cipher with only a 56-bit key</strong>. The only reason anyone could have for
using a 56 or 64-bit key is to comply with various <a
href="exportlaw.html">export laws</a> intended to ensure the use of breakable
ciphers.</p>
<p>Non-government cryptologists have been saying DES's 56-bit key was too
short for some time -- some of them were saying it in the 70's when DES
became a standard -- but the US government has consistently ridiculed such
suggestions.</p>
<p>A group of well-known cryptographers looked at key lengths in a <a
href="http://www.counterpane.com/keylength.html"> 1996 paper</a>. They
suggested a <em>minimum</em> of 75 bits to consider an existing cipher secure
and a <em>minimum of 90 bits for new ciphers</em>. More recent papers,
covering both <a href="glossary.html#symmetric">symmetric</a> and <a
href="glossary.html#public">public key</a> systems are at <a
href="http://www.cryptosavvy.com/">cryptosavvy.com</a> and <a
href="http://www.rsasecurity.com/rsalabs/bulletins/bulletin13.html">rsa.com</a>.
For all algorithms, the minimum keylengths recommended in such papers are
significantly longer than the maximums allowed by various export laws.</p>
<p>In a <a
href="http://www.privacy.nb.ca/cryptography/archives/cryptography/html/1998-09/0095.html">1998
ruling</a>, a German court described DES as "out-of-date and not safe enough"
and held a bank liable for using it.</p>
<h3><a name="deshware">Dedicated hardware breaks DES in a few days</a></h3>
<p>The question of DES security has now been settled once and for all. In
early 1998, the <a href="http://www.eff.org/">Electronic Frontier
Foundation</a> built a <a
href="http://www.eff.org/descracker.html">DES-cracking machine</a>. It can
find a DES key in an average of a few days' search. The details of all this,
including complete code listings and complete plans for the machine, have
been published in <a href="biblio.html#EFF"><cite>Cracking DES</cite></a>, by
the Electronic Frontier Foundation.</p>
<p>That machine cost just over $200,000 to design and build. "Moore's Law" is
that machines get faster (or cheaper, for the same speed) by roughly a factor
of two every 18 months. At that rate, their $200,000 in 1998 becomes $50,000
in 2001.</p>
<p>However, Moore's Law is not exact and the $50,000 estimate does not allow
for the fact that a copy based on the published EFF design would cost far
less than the original. We cannot say exactly what such a cracker would cost
today, but it would likely be somewhere between $10,000 and $100,000.</p>
<p>A large corporation could build one of these out of petty cash. The cost
is low enough for a senior manager to hide it in a departmental budget and
avoid having to announce or justify the project. Any government agency, from
a major municipal police force up, could afford one. Or any other group with
a respectable budget -- criminal organisations, political groups, labour
unions, religious groups, ... Or any millionaire with an obsession or a
grudge, or just strange taste in toys.</p>
<p>One might wonder if a private security or detective agency would have one
for rent. They wouldn't need many clients to pay off that investment.</p>
<h3><a name="spooks">Spooks may break DES faster yet</a></h3>
<p>As for the security and intelligence agencies of various nations, they may
have had DES crackers for years, and theirs may be much faster. It is
difficult to make most computer applications work well on parallel machines,
or to design specialised hardware to accelerate them. Cipher-cracking is one
of the very few exceptions. It is entirely straightforward to speed up
cracking by just adding hardware. Within very broad limits, you can make it
as fast as you like if you have the budget. The EFF's $200,000 machine breaks
DES in a few days. An <a href="http://www.planepage.com/">aviation
website</a> gives the cost of a B1 bomber as $200,000,000. Spending that
much, an intelligence agency could break DES in an average time of <em>six
and a half minutes</em>.</p>
<p>That estimate assumes they use the EFF's 1998 technology and just spend
more money. They may have an attack that is superior to brute force, they
quite likely have better chip technology (Moore's law, a bigger budget, and
whatever secret advances they may have made) and of course they may have
spent the price of an aircraft carrier, not just one aircraft.</p>
<p>In short, we have <em>no idea</em> how quickly these organisations can
break DES. Unless they're spectacularly incompetent or horribly underfunded,
they can certainly break it, but we cannot guess how quickly. Pick any time
unit between days and milliseconds; none is entirely unbelievable. More to
the point, none of them is of any comfort if you don't want such
organisations reading your communications.</p>
<p>Note that this may be a concern even if nothing you do is a threat to
anyone's national security. An intelligence agency might well consider it to
be in their national interest for certain companies to do well. If you're
competing against such companies in a world market and that agency can read
your secrets, you have a serious problem.</p>
<p>One might wonder about technology the former Soviet Union and its allies
developed for cracking DES during the Cold War. They must have tried; the
cipher was an American standard and widely used. Certainly those countries
have some fine mathematicians, and those agencies had budget. How well did
they succeed? Is their technology now for sale or rent?</p>
<h3><a name="desnet">Networks break DES in a few weeks</a></h3>
<p>Before the definitive EFF effort, DES had been cracked several times by
people using many machines. See this <a
href="http://www.distributed.net/pressroom/DESII-1-PR.html"> press
release</a> for example.</p>
<p>A major corporation, university, or government department could break DES
by using spare cycles on their existing collection of computers, by
dedicating a group of otherwise surplus machines to the problem, or by
combining the two approaches. It might take them weeks or months, rather than
the days required for the EFF machine, but they could do it.</p>
<p>What about someone working alone, without the resources of a large
organisation? For them, cracking DES will not be easy, but it may be
possible. A few thousand dollars buys a lot of surplus workstations. A pile
of such machines will certainly heat your garage nicely and might break DES
in a few months or years. Or enroll at a university and use their machines.
Or use an employer's machines. Or crack security somewhere and steal the
resources to crack a DES key. Or write a virus that steals small amounts of
resources on many machines. Or . . .</p>
<p>None of these approaches are easy or break DES really quickly, but an
attacker only needs to find one that is feasible and breaks DES quickly
enough to be dangerous. How much would you care to bet that this will be
impossible if the attacker is clever and determined? How valuable is your
data? Are you authorised to risk it on a dubious bet?</p>
<h3><a name="no_des">We disable DES</a></h3>
<p>In short, it is now absolutely clear that <strong>DES is not
secure</strong> against</p>
<ul>
<li>any <strong>well-funded opponent</strong></li>
<li>any opponent (even a penniless one) with access (even stolen access) to
<strong>enough general purpose computers</strong></li>
</ul>
<p>That is why <strong>Linux FreeS/WAN disables all transforms which use
plain DES</strong> for encryption.</p>
<p>DES is in the source code, because we need DES to implement our default
encryption transform, <a href="glossary.html#3DES">Triple DES</a>. <strong>We
urge you not to use single DES</strong>. We do not provide any easy way to
enable it in FreeS/WAN, and our policy is to provide no assistance to anyone
wanting to do so.</p>
<h3><a name="40joke">40-bits is laughably weak</a></h3>
<p>The same is true, in spades, of ciphers -- DES or others -- crippled by
40-bit keys, as many ciphers were required to be until recently under various
<a href="#exlaw">export laws</a>. A brute force search of such a cipher's
keyspace is 2<sup>16</sup> times faster than a similar search against DES.
The EFF's machine can do a brute-force search of a 40-bit key space in
<em>seconds</em>. One contest to crack a 40-bit cipher was won by a student
<a href="http://catless.ncl.ac.uk/Risks/18.80.html#subj1"> using a few
hundred idle machines at his university</a>. It took only three and half
hours.</p>
<p>We do not, and will not, implement any 40-bit cipher.</p>
<h3><a name="altdes">Triple DES is almost certainly secure</a></h3>
<p><a href="glossary.html#3DES">Triple DES</a>, usually abbreviated 3DES,
applies DES three times, with three different keys. DES seems to be basically
an excellent cipher design; it has withstood several decades of intensive
analysis without any disastrous flaws being found. It's only major flaw is
that the small keyspace allows brute force attacks to succeeed. Triple DES
enlarges the key space to 168 bits, making brute-force search a ridiculous
impossibility.</p>
<p>3DES is currently the only block cipher implemented in FreeS/WAN. 3DES is,
unfortunately, about 1/3 the speed of DES, but modern CPUs still do it at
quite respectable speeds. Some <a href="glossary.html#benchmarks">speed
measurements</a> for our code are available.</p>
<h3><a name="aes.ipsec">AES in IPsec</a></h3>
<p>The <a href="glossary.html#AES">AES</a> project has chosen a replacement
for DES, a new standard cipher for use in non-classified US government work
and in regulated industries such as banking. This cipher will almost
certainly become widely used for many applications, including IPsec.</p>
<p>The winner, announced in October 2000 after several years of analysis and
discussion, was the <a
href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">Rijndael</a> cipher
from two Belgian designers.</p>
<p>It is almost certain that FreeS/WAN will add AES support. <a
href="web.html#patch">AES patches</a> are already available.</p>
<h2><a name="press">Press coverage of Linux FreeS/WAN:</a></h2>
<h3>FreeS/WAN 1.0 press</h3>
<ul>
<li><a
href="http://www.wired.com/news/news/technology/story/19136.html">Wired</a>
"Linux-Based Crypto Stops Snoops", James Glave April 15 1999</li>
<li><a
href="http://slashdot.org/articles/99/04/15/1851212.shtml">Slashdot</a></li>
<li><a href="http://dgl.com/itinfo/1999/it990415.html">DGL</a>, Damar Group
Limited; looking at FreeS/WAN from a perspective of business
computing</li>
<li><a href="http://linuxtoday.com/stories/5010.html">Linux Today</a></li>
<li><a href="http://www.tbtf.com/archive/1999-04-21.html#Tcep">TBTF</a>,
Tasty Bits from the Technology Front</li>
<li><a
href="http://www.salonmagazine.com/tech/log/1999/04/16/encryption/index.html">Salon
Magazine</a> "Free Encryption Takes a Big Step"</li>
</ul>
<h3><a name="release">Press release for version 1.0</a></h3>
<pre> Strong Internet Privacy Software Free for Linux Users Worldwide
Toronto, ON, April 14, 1999 -
The Linux FreeS/WAN project today released free software to protect
the privacy of Internet communications using strong encryption codes.
FreeS/WAN automatically encrypts data as it crosses the Internet, to
prevent unauthorized people from receiving or modifying it. One
ordinary PC per site runs this free software under Linux to become a
secure gateway in a Virtual Private Network, without having to modify
users' operating systems or application software. The project built
and released the software outside the United States, avoiding US
government regulations which prohibit good privacy protection.
FreeS/WAN version 1.0 is available immediately for downloading at
http://www.xs4all.nl/~freeswan/.
"Today's FreeS/WAN release allows network administrators to build
excellent secure gateways out of old PCs at no cost, or using a cheap
new PC," said John Gilmore, the entrepreneur who instigated the
project in 1996. "They can build operational experience with strong
network encryption and protect their users' most important
communications worldwide."
"The software was written outside the United States, and we do not
accept contributions from US citizens or residents, so that it can be
freely published for use in every country," said Henry Spencer, who
built the release in Toronto, Canada. "Similar products based in the
US require hard-to-get government export licenses before they can be
provided to non-US users, and can never be simply published on a Web
site. Our product is freely available worldwide for immediate
downloading, at no cost."
FreeS/WAN provides privacy against both quiet eavesdropping (such as
"packet sniffing") and active attempts to compromise communications
(such as impersonating participating computers). Secure "tunnels" carry
information safely across the Internet between locations such as a
company's main office, distant sales offices, and roaming laptops. This
protects the privacy and integrity of all information sent among those
locations, including sensitive intra-company email, financial transactions
such as mergers and acquisitions, business negotiations, personal medical
records, privileged correspondence with lawyers, and information about
crimes or civil rights violations. The software will be particularly
useful to frequent wiretapping targets such as private companies competing
with government-owned companies, civil rights groups and lawyers,
opposition political parties, and dissidents.
FreeS/WAN provides privacy for Internet packets using the proposed
standard Internet Protocol Security (IPSEC) protocols. FreeS/WAN
negotiates strong keys using Diffie-Hellman key agreement with 1024-bit
keys, and encrypts each packet with 168-bit Triple-DES (3DES). A modern
$500 PC can set up a tunnel in less than a second, and can encrypt
6 megabits of packets per second, easily handling the whole available
bandwidth at the vast majority of Internet sites. In preliminary testing,
FreeS/WAN interoperated with 3DES IPSEC products from OpenBSD, PGP, SSH,
Cisco, Raptor, and Xedia. Since FreeS/WAN is distributed as source code,
its innards are open to review by outside experts and sophisticated users,
reducing the chance of undetected bugs or hidden security compromises.
The software has been in development for several years. It has been
funded by several philanthropists interested in increased privacy on
the Internet, including John Gilmore, co-founder of the Electronic
Frontier Foundation, a leading online civil rights group.
Press contacts:
Hugh Daniel, +1 408 353 8124, hugh@toad.com
Henry Spencer, +1 416 690 6561, henry@spsystems.net
* FreeS/WAN derives its name from S/WAN, which is a trademark of RSA Data
Security, Inc; used by permission.</pre>
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