Jefferson’s Wheel

Nate Paul, who finished a PhD in our group a few years ago and is now a research scientist at Oak Ridge National Labs, is the focus of this CNN story: Scientists work to keep hackers out of implanted medical devices, CNN, 16 April 2010.

Nathanael Paul likes the convenience of the insulin pump that regulates his diabetes. It communicates with other gadgets wirelessly and adjusts his blood sugar levels automatically.

But, a few years ago, the computer scientist started to worry about the security of this setup.

What if someone hacked into that system and sent his blood sugar levels plummeting? Or skyrocketing? Those scenarios could be fatal.

“If your computer fails, no one dies,” he said in a phone interview. “If your insulin pump fails, you have problems.”

As sci-fi as it sounds, Paul’s fears are founded in reality.
…

The New York Times has an article about rigging the World Cup draw (which takes place tomorrow in South Africa): In World Cup Draw, Conspiracy Theories Abound, 3 December 2009.

The article mentions the final exam from my 2005 Cryptography course:

It is anyone’s guess how the 32 teams in the 2010 World Cup will be grouped by the draw Friday in South Africa, but one thing is for sure: the event will elicit sightings of things as far-fetched as U.F.O.’s and the Virgin Mary’s image on a potato chip.

…

Yet conspiracy theories abound. In 2005, the issue was part of a final exam in a cryptology course at the University of Virginia.

Here’s the actual exam: http://www.cs.virginia.edu/cs588/final/final.html and an excerpt from my comments:

4W. Germany 1, USA 0

After the 1994 World Cup draw placed the host USA in a very difficult
group, the USA coach, Bora Milutinovic, is reputed to have complained
that the US organizing committee was so incompetent they couldn’t even
rig the draw properly. For purposes of this question, assume the DFB
(German soccer federation) which is hosting the 2006 World Cup does not
suffer from such incompetence.

The draw assigns each qualified team to a group (one of eight, A-H) and
position (1-4). For example, in the 2002 draw the USA was assigned D3.
The host country is placed into position A1.

The protocol for the draw for the 2006 World Cup finals has not been
announced yet, but assume it will follow a protocol similar to this one
which was used in 2002:

Before the draw event:
1. The name of each finalist (except the host country which is placed
   in position A1) is printed on a slip of paper which is placed in a
   white, spherical ball. The ball is made of two hemispheres that connect
   to each other, and can be separated to insert or remove the paper. The
   balls are placed into different bowls based on a partitioning determined
   by FIFA.
2. The letter name to identify each group (A, B, C, D, E, F, G, H) is
   printed on a slip of paper and placed in a red, spherical ball. All the
   red balls are placed in a bowl.
3. The position number (1, 2, 3, 4) is printed on a slip of paper and
   placed in a blue, spherical ball. There are eight bowls of the four
   numbers, one corresponding to each group A-H. (In the bowl for A, only
   three balls with numbers 2, 3 and 4 are used, since the host country was
   preassigned to position A1).

   At the draw event:

4. A well-known celebrity picks a white ball from one of the country
   bowls and hands it to Sepp Blatter, the President of FIFA.
5. Blatter unscrews the ball, extracts the slip of paper, reads the
   country name, and holds it up so everyone can see. After reading the
   slip, it is placed in a trash bin that is not examined after the draw.
6. A different well-known celebrity picks a red ball from the
   group bowl and hand it to Blatter.
7. Blatter unscrews the ball, extracts the slip of paper, reads the
   group name, and holds it up so everyone can see.
8. A different well-known celebrity picks a blue ball from the
   positions bowl corresponding to the selected group and hand it to Blatter.
9. Blatter unscrews the ball, extracts the slip of paper, reads the
   position number, and holds it up so everyone can see.

Note that at the end of the draw, all balls have been opened. It is a
check on the protocol that all positions, groups and countries have been
seen by the end. The actual slips of paper are destroyed (without
examination) after the draw.

You should assume both the DFB who is hosting the draw, and Sepp
Blatter, are both highly motivated to rig the results to ensure an easy
path to the second round for the host country. Well-known celebrities
are used to pick the balls to ensure a low likelihood that a selector
can be corrupted. The pre-draw steps are done in secret by the DFB.
The draw event itself is witnessed by thousands of people live and in
person and approximately a billion people live on TV around the world
(it is the world’s most watched televised event that is not a soccer
game).

Analyze the security of the World Cup draw procedure as described
above. Either describe tactics the DFB could use to improve the
likelihood that Germany get a favorable draw, or argue that the
procedure is secure and there is no reasonable way of effecting the
result. If you identify security weaknesses in the draw protocol,
suggest modifications that would make it more secure.

For inspiration, you may want to read Bruce Schneier’s Hacking the Papal Election analysis of the Papal election procedure.

(Note: this question should in no way be interpreted as
questioning the integrity of FIFA or the DFB, especially if they are
using RFID tags to track my tickets’ whereabouts.)

Comments: There are lots of weaknesses in the described protocol
(which does not match the actual world cup draw protocol which may have even more vulnerabilities) that could be used to alter the draw outcome.

Some improvements that would make cheating more difficult would be to have an independent third party create the balls in public, to have a multiple-readers strategy like in the Pope election where several people examine each slip in public, to have the celebrities (considered uncorruptable) not only pick the ball but open it and examine the slip before it is read, and to have all the balls selected before any one it opened (to prevent any attacks that depend on knowing what was in the previous ball to pick a desirable ball).

From the NYT article, I may be mistaken about the rumors of Bora Milutinovic’s comments about the 1994 draw. Perhaps it was really Bruce Arena’s quote about the draw for the 1996 Olympics, quoted in the NYT article which is presumably a fairly reputable source.

As for tomorrow’s draw, so long as the US doesn’t end up in a group with Brazil, France, and Ivory Coast, I’m willing to assume its not rigged.

IEEE Spectrum has an article on Karsten Nohl’s efforts to lead an open-source GSM hacking project: Open-Source Effort to Hack GSM, IEEE Spectrum, 30 November 2009.

If you’re still using a cellphone based on early digital standards, you better be careful what you say. The encryption technology used to prevent eavesdropping in GSM (Global System for Mobile communications), the world’s most widely used cellphone system, has more security holes than Swiss cheese, according to an expert who plans to poke a big hole of his own.

Karsten Nohl, chief research scientist with H4RDW4RE, a Sunnyvale, Calif.-based security research firm, is mounting what could be the most ambitious attempt yet to compromise the GSM phone system, which is used by over 3 billion people around the world. Others have cracked the A5/1 encryption technology used in GSM before, but their results have remained secret. However, Nohl, who earned a Ph.D. in computer science at the University of Virginia and is a member of Germany’s Chaos Computer Club (CCC), intends to go one big step further: By the end of the year, he plans to make the keys available to everyone on the Internet.

…

GSM cracking has a long history, which began in the late 1990s in academic circles and has since sprouted a handful of commercial businesses. Today, these companies legally sell GSM call-interception solutions–which are relatively expensive–mostly to government intelligence agencies. In general, supplying and using this software is illegal in the wider market, but no one can say for certain how many groups have illegally gained access to the technology.

That’s the point Nohl hopes to drive home: The A5/1 algorithm is a broken 64-bit encryption technology, a relic of the Cold War era, when laws prohibited the export of strong encryption technology from the United States. It needs to be replaced–ideally by the much stronger, 128-bit A5/3 system, which is already being used in newer-generation digital cellular systems, such as Universal Mobile Telecommunications System (UMTS). “If you go from the 64 bits of the A5/1 cipher to the 128 bits of A5/3,” says Nohl, cracking requires an amount of memory storage that is beyond what “is available on earth.”

A big problem with plugging the GSM encryption hole, according to the security expert, is that operators are unwilling to admit that a problem even exists. Many want to avoid spending additional money on upgrading aging and amortized GSM infrastructure, he says. The GSM Association, which represents the interests of GSM mobile operators around the world, says only that it is aware of various eavesdropping projects. In the same breath, it points to the complexities of identifying and recording calls from RF signals.

British Prime Minister Gordon Brown has issued a long overdue apology to Alan Turing on behalf of the British government. The full text is here.

Turing was a quite brilliant mathematician, most famous for his work on breaking the German Enigma codes. It is no exaggeration to say that, without his outstanding contribution, the history of World War Two could well have been very different. He truly was one of those individuals we can point to whose unique contribution helped to turn the tide of war. The debt of gratitude he is owed makes it all the more horrifying, therefore, that he was treated so inhumanely. In 1952, he was convicted of ‘gross indecency’ – in effect, tried for being gay. His sentence – and he was faced with the miserable choice of this or prison – was chemical castration by a series of injections of female hormones. He took his own life just two years later.

… But even more than that, Alan deserves recognition for his contribution to humankind. For those of us born after 1945, into a Europe which is united, democratic and at peace, it is hard to imagine that our continent was once the theatre of mankind’s darkest hour. It is difficult to believe that in living memory, people could become so consumed by hate – by anti-Semitism, by homophobia, by xenophobia and other murderous prejudices – that the gas chambers and crematoria became a piece of the European landscape as surely as the galleries and universities and concert halls which had marked out the European civilisation for hundreds of years. It is thanks to men and women who were totally committed to fighting fascism, people like Alan Turing, that the horrors of the Holocaust and of total war are part of Europe’s history and not Europe’s present.

So on behalf of the British government, and all those who live freely thanks to Alan’s work I am very proud to say: we’re sorry, you deserved so much better.

The apology grew out of an online petition initiated by John Graham-Cumming (also known for writing the Geek Atlas travel guide). Britain has a long tradition of citizens being able to petition the government, which is now supported by an e-petitions website. The petition asking for an apology to Alan Turing is currently the fourth-most signed petition with 31,349 signatures (all of whom must be British citizens).

Some news coverage:

• BBC: PM apology after Turing petition
• The Guardian: No 10 apologises for “appalling” treatment of Alan Turing
• John Graham-Cumming’s blog: “Hello John, It’s Gordon Brown”

Technology Review has an article surveying the state of RFID security: RFID’s Security Problem, Technology Review, January/February 2009. It focuses on security and privacy issues related to RFID-enabled passports and driver’s licenses.

Excerpt: (bolding is mine)

Meanwhile, although experts say that some RFID technologies are quite secure, a University of Virginia security researcher’s analysis of the NXP Mifare Classic (see Hack, November/December 2008), an RFID chip used in fare cards for the public-­transit systems of ­Boston, London, and other cities, has shown that the security of smart cards can’t be taken for granted. “I think we are in the growing-pains phase,” says Johns Hopkins University computer science professor Avi Rubin, a security and privacy researcher. “This happens with a lot of technologies when they are first developed.”

…
As long as the remaining problems are ignored, though, it’s unlikely that the technology will become good enough to protect international borders without compromising the privacy of thousands or millions of people. Tadayoshi Kohno, for one, says that at this point, he is not convinced that RFID even offers security advantages over the old IDs. Technology used on this scale, and for purposes this important, should be clearly better than what it’s replacing: the U.S. experience with electronic voting systems shows what can happen when it’s not. If officials continue to advocate band-aids such as privacy sleeves rather than working to address the full extent of critics’ concerns, they will ultimately undermine the very technology that they hope to promote. While new ID technology seems likely to stay, it could become a fiasco if officials don’t pay attention to the work of hackers and security researchers. These people try to expose weaknesses before they can be exploited maliciously. It’s much less painful to swallow the news from them than to wait until a problem becomes embarrassing–or devastating.

Jonathan McCune successfully defended his PhD thesis at Carnegie Mellon University last week. Jon (sorry, that’s “Dr. McCune”) was an undergraduate researcher in our group from 2001-2003, when he worked on agent-based software (for our RoboCup team) and adaptable sensor network security, before joining CMU’s PhD program in 2003. Dr. McCune’s recent research has focused on leveraging trusted hardware to build secure systems.

Congratulations Dr. McCune!

UVa Today has an article about our (myself, abhi shelat, John Lach, and Ben Calhoun) recent NSF Cybertrust grant on RFID security and privacy: U.Va. Team Receives $1 Million Grant To Improve RFID Security, by Brevy Cannon, 9 January 2009.

Some excerpts:

To address the problematic use of custom cryptography, the U.Va. research team will develop an encryption scheme that is relatively strong — providing some measure of privacy and security — but that can be implemented at almost zero cost by repurposing the meager hardware resources already available on common RFID tags. Providing a solution that adds virtually no cost is crucial, because these RFIDs are made by the billions, at such low costs (5 cents or less apiece) that there is no margin for any added expense.

…

The team is breaking new ground by using a holistic design approach that considers how all the various levels of the design — the hardware, the encryption algorithm and how it is used — work together, mindful of how an attacker will target the single weakest link in the design.

…

The research team hopes their research will forestall that possibility, enabling RFIDs to be used in countless ingenious applications not yet dreamt of, without sacrificing privacy and security in a Faustian bargain.

The November/December 2008 Technology Review Hack, How Smart Is a Smart Card?”, describes Karsten Nohl’s work on reverse engineering the Mifare Classic. In includes a video of a card dissolving, and some great images.

The full details of the Crypto-1 cipher (initially exposed back in December) have now been released.

They are published in Appendix A of Henryk Plötz’s thesis report: Mifare Classic – Eine Analyse der Implementierung. The thesis is in German, but the algorithm is published as a C program (by Karsten Nohl, Henryk Plötz and Sean O’Neil), so should be understandable to non-German code readers.

Also yesterday, the paper, Dismantling MIFARE Classic, by Flavio D. Garcia, Gerhard de Koning Gans, Ruben Muijrers, Peter van Rossum, Roel Verdult, Ronny Wichers Schreur, and Bart Jacobs of Radboud University Nijmegen, The Netherlands, appeared at ESORICS 2008. This is the paper that was the subject of NXP’s failed lawsuit.

The publication of these details remove any remaining doubts about the insecurity of the Mifare Classic.

News articles:

D-Day for RFID-based transit card systems, c|net News, 6 October 2008.

“Combining these two pieces of information, attacks can now be implemented by anyone,” RFID researcher Karsten Nohl told CNET News. “All it takes is a $100 (card) reader and a little software.”
…
Security systems like the Mifare Classic that are not peer reviewed are not as trustworthy as systems that can be openly analyzed by researchers looking for flaws, Johanson and Nohl said.

“Developing your own proprietary security mechanisms and not getting public scrutiny on it does not work,” Nohl said.

Boffins (finally) publish hack for world’s most popular smartcard, The Register, 6 October 2008.

Two research papers published Monday have finally made it official: The world’s most widely deployed radio frequency identification (RFID) smartcard – used to control access to transportation systems, military installations, and other restricted areas – can be cracked in a matter of minutes using inexpensive tools.

The two documents combined mean that virtually anyone with the time and determination can carry out the attacks, said Karsten Nohl, a PhD candidate at the University of Virginia and one of the cryptographers who first warned of the weakness in December.

“Now the weakness that we and others have been talking about for months can be verified independently by really anybody,” he said. “The flip side is that everybody can now attack Mifare-based security systems.”

Over the past six months, many organizations that rely on the Mifare Classic have upgraded their systems, but Nohl said he is personally aware of a “handful” of systems used by government agencies or large multinational companies that have been unable to make the necessary changes because of the logistical challenges of issuing new badges to employees.

“One hopes that just based on the announcement, most operators of critical security systems have adopted other technologies besides Mifare,” Nohl said.

Update: (10 Oct) Another article from the CBC: Security flaw in smart cards poses risk for transit, building access, CBC News, 10 October, 2008.

Verayo is the second company to announce the "World’s first unclonable RFID tag" based on a physically unclonable function (PUF), after Veratag announced a similar product based on PUF technology. The security claims of these and other PUF-based products seem dubious since the current realization of PUFs defies basic principles of cryptography. The announcement states:

This new RFID chip is based on recently announced breakthrough technology called Physical Unclonable Functions (PUF). PUF technology is a type of electronic DNA or fingerprinting technology for silicon chips that makes each chip unclonable.

It might be besides the point that neither DNA, nor fingerprints are unclonable. The failure of proprietary security, which has been a constant theme on this blog, has led many to conclude that only well-reviewed security primitives can be strong. PUF technology tries to achieve security in exactly the opposite way: the PUF circuit is designed in a way so that not even the designer understands how outputs are derived from inputs. Security-by-obscurity par excellence.

Every circuit, including PUFs, is a deterministic function; the only difference in PUF circuits is that some inputs to the function vary across different tags. For a PUF to be cryptographically strong, one would hence need to show that

1. the fixed part of the circuit (the cipher) is strong by cryptographic metrics,
2. the number of device-dependent inputs (the secret key) is large and
3. the entropy of these inputs is high.

PUFs are a wonderful idea for using manufacturing variance constructively, but in their current realization, PUFs fail to convince that they are strong building blocks for security systems.