Category Archives: Mathematics

Rogue CA – MD5 collisions for phun and profit

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Now this is, umm, interesting..

We have identified a vulnerability in the Internet Public Key Infrastructure (PKI) used to issue digital certificates for secure websites. As a proof of concept we executed a practical attack scenario and successfully created a rogue Certification Authority (CA) certificate trusted by all common web browsers. This certificate allows us to impersonate any website on the Internet, including banking and e-commerce sites secured using the HTTPS protocol.

Trust no one..

(Via)

A Tale of Two Transport Hacks

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In the USA a court has ordered that three MIT students not talk at DEFCON about their security assessment of the Massachusetts Bay Transit Authority (MBTA) fare cards. Apparently the court believes that “discussing the flaws at a public conference constituted a ‘transmission’ of a computer program that could harm the fare collection system“, which is pretty sad. There are more documents at Cryptome on the case. Their presentation was to include a cryptanalysis of the Mifare “Classic” card, which takes us to our second case..

Bruce Schneier reports that a group of Dutch researchers have won in court to be able to publish their own cryptanalysis of that very same Mifare Classic card, with the court stating:

Damage to NXP is not the result of the publication of the article but of the production and sale of a chip that appears to have shortcomings.

An outbreak of common sense that the MIT students could only dream of. I wonder if they could appeal and cite this case as grounds to have the judgement overturned ?

Applying Graphics Cards to Password Cracking

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On the Beowulf list there has been a long thread on GPGPU and especially nVidia’s CUDA language. As part of it Prentice Bisbal posted about a friend of his, Mario Juric, who decided to write a proof of concept MD5 password hashing program to take advantage of CUDA.

In his message to the Beowulf list Prentice quoted Mario saying:

If you attempt to compute a single hash on an entire card, you won’t get any improvement. Same as you wouldn’t if you tried it on a single vs. quad core CPU. But if you compute four hashes, than single vs. quad makes a huge difference. And the GPU cards are effectively 128 core CPUs, so when you need to compute millions of hashes…

Now Mario Juric (who organised the AstroGPU workshop) has put up a web page on the program, which gives details of the sort of performance he got with a quick hack.

One way of visualizing this is noting that a single 8800 Ultra could brute-force break an MD5 hashed password of eight or less characters+numbers (A-Z, a-z, 0-9) in about ~16 days.

But this really is just a quick hack:

The MD5 code used here was written in less than 2 days, as a proof-of-concept, and with only a single one-liner GPU-specific optimization.

Of course if people do want to try playing with it the program is available, though at the moment there isn’t a software license included with it. I’ve emailed Mario about the license to see if he can clarify what the rules are.

Bletchley Park in Cash Trouble ?

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For the past few weeks I’ve been reading “Codebreakers“, a collection of memoirs and essays by former staff at Bletchley Park, aka the Government Code and Cipher School (GCCS) War Station-X, Room 47 Foreign Office, etc. which worked throughout the war breaking enemy ciphers such as the German Enigma machine, the decrypts of which were called “Ultra“.

But today, via Bruce Scheiers blog, I’ve learnt that the trust that now runs BP has is facing financial problems as they receive no external funding and need cash to help preserve the buildings and the exhibits they restored after taking over the site in the 1990s.

The Bletchley Park Trust receives no external funding. It has been deemed ineligible for funding by the National Lottery, and turned down by the Bill & Melinda Gates Foundation because the Microsoft founder will only fund internet-based technology projects.

For the site that hosted the organisation that arguably saved the day in World War 2, not to mention being the birthplace of the first real computer, Colossus (( yes, I know it wasn’t Turing complete! )), it’s a sad predicament. 🙁

Ross Anderson’s “Security Engineering”

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Back in 2006 Ross Anderson (Professor of Security Engineering at the Cambridge Computer Laboratory) announced on his blog that he had published the full contents of the first edition of his book “Security Engineering” in PDF format. The book covers a whole range of security issues from creating, managing, accrediting & breaking the mechanisms themselves through security politics and into topics like DRM.

Now the second edition of Security Engineering is about to arrive (published April 14th in the US, Amazon say stock expected in 1-4 weeks) and mine is on order already (along with a copy of Linus Torvalds Just for Fun).. 🙂

Taking the Myki ?

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So Melbourne is investigating an electronic tag based ticketing system for public transport called Myki (presumably meant to be pronounced My Key and not mickey), and in an interesting coincidence Bruce Schneier reports a successful attack against a Dutch ticketing system that’s about to be deployed:

The first reported attack was designed by two students at the University of Amsterdam, Pieter Siekerman and Maurits van der Schee. They analyzed the single-use ticket and showed its vulnerabilities in a report. They also showed how a used single-use card could be given eternal life by resetting it to its original “unused” state.

The second attack is a reverse engineering of the crypto algorithm through a physical attack on the circuitry which will be a jumping off point for further attacks, I guess.

I wonder how long it’ll take for the Melbourne system to be similarly compromised ?

Compare and Contrast – Pre-entrance Chinese University Question and First Year UK University Question

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For anyone who doubts that graduates in China are going to be more than a match for the rest of the world, go and read this BBC news article comparing a maths question set to first year chemistry students in the UK with a maths question that is set to students wishing to enter university in China.

The Royal Society of Chemistry in the UK is running a competition offering a GBP500 prize to a winner who can correctly answer the question from China. This is because of their concerns about the poor level of mathematics that Chemistry students in the UK have:

Increasingly, universities are mounting remedial sessions for incoming science undergraduates because their maths skills are so limited, with many having stopped formal lessons in mathematics two years earlier at the GCSE level.

US Wants to Remove More Rights, Expand DMCA

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It would appear a coalition of the repressive wish to expand the remit of US Copyright law, including the DMCA, to make it even harder to do research, play media on any OS but those you have to payed Microsoft/Apple for, or defend yourself against damaging software they put on silver circles they claim to be (but are not) Compact Discs.

Jessica Litman, who teaches copyright law at Wayne State University, views the DMCA expansion as more than just a minor change. “If Sony had decided to stand on its rights and either McAfee or Norton Antivirus had tried to remove the rootkit from my hard drive, we’d all be violating this expanded definition,” Litman said.

Even the current wording of the DMCA has alarmed security researchers. Ed Felten, the Princeton professor, told the Copyright Office last month that he and a colleague were the first to uncover the so-called “rootkit” on some Sony BMG Music Entertainment CDs–but delayed publishing their findings for fear of being sued under the DMCA.

..and how do they propose to get this through ? Fear of course! That resurgent American political tool.

During a speech in November, Attorney General Alberto Gonzales endorsed the idea and said at the time that he would send Congress draft legislation. Such changes are necessary because new technology is “encouraging large-scale criminal enterprises to get involved in intellectual-property theft,” Gonzales said, adding that proceeds from the illicit businesses are used, “quite frankly, to fund terrorism activities.”

Ed: my emphasis added