david wong

Hey! I'm David, a security consultant at Cryptography Services, the crypto team of NCC Group . This is my blog about cryptography and security and other related topics that I find interesting.

Réseaux

posted November 2013

I have an exam of Réseaux (Network) tomorrow and the slides of my prof are... how could I say this... not really clear. We have practical applications classes but they were... organized in the worst possible way. The subject did seem interesting at first but I felt like I learned nothing. Hopefully for the past few weeks I've been using the wonderful online course An Introduction to Computer Networks given by Nick McKeown and Philip Levis both very competent profs from Stanford. It seems like I should have gone there for my master of Cryptography :) Anyway, I'm doing with what I have here and I feel blessed studying Cryptography right when free online courses started becoming a thing.

The course is available here.

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Bullrun

posted November 2013

Bullrun or BULLRUN is a clandestine, highly classified decryption program run by the United States National Security Agency (NSA). The British signals intelligence agency Government Communications Headquarters (GCHQ) has a similar program codenamed Edgehill. According to the NSA's BULLRUN Classification Guide, which was published by The Guardian, BULLRUN is not a Sensitive Compartmented Information (SCI) control system or compartment, but the codeword has to be shown in the classification line, after all other classification and dissemination markings. Information about the program's existence was leaked in 2013 by Edward Snowden.

from https://en.wikipedia.org/wiki/Bullrun_%28decryption_program%29" target="_blank">wikipedia.

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Sudoku Solver

posted November 2013

My Programmmation class first part is about coding a sudoku solver. We have to do everything in english, we have to commit with svn, we have to write a final report with LaTeX.

Every week we're given some vague guidelines and we have to dive deep into C to first, understand what we have to do, and secondly, find solutions in a language we've never really played with before. We have to turn in what we did every week, if our code doesn't compile it's a zero, if it does compile it goes through a multitude of tests that quickly decrease your grade (out of 20). Let's just say I spent many nights and early mornings coding and I started the first week with a 2/20.

It felt like a crash course, it felt unfair at times, but holy cow did I learn some C in a really short amount of time. Props to my professor for that, and I wish I had more courses like that. I might not get the best grade out of this course but I sure learn the most things there.

I've also committed everything I've done on a public git repo so everyone can see how it looks like here :

https://github.com/mimoo/sudoku

You can compile with make, learn how to use with ./sudoku -h

It can read sudokus of different sizes from 1x1 to 64x64 as long as it is presented like this :

#this is a comment

5 3 _ _ 7 _ _ _ _

6 _ _ 1 9 5 _ _ _

_ 9 8 _ _ _ _ 6 _

8 _ _ _ 6 _ _ _ 3

4 _ _ 8 _ 3 _ _ 1

7 _ _ _ 2 _ _ _ 6

_ 6 _ _ _ _ 2 8 _

_ _ _ 4 1 9 _ _ 5

_ _ _ _ 8 _ _ 7 9
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One more list

posted November 2013

It's time for a new list of random things I noticed about Bordeaux :

  • Many 2€ kebab places. Also, kebab here are made with a Lebanese bread, like a crepe, and not with the half of an Arabic bread like in Lyon.
  • It's raining, A LOT. It's raining at least once a week, but usually way more than once a week.
  • It's not that cold. I just came back from a week in Lyon and oh my god was it cold there, you can feel winter coming, but in Bordeaux ? Chill, you don't need that jacket.
  • There are no Bordelais. Most people I run into come from other places in France. I actually only met one Bordelaise and it was during my first week here.
  • The city is really not that big. In 30 minutes you feel like you've seen most of it.
  • We have Velov' in Lyon, Velib' in Paris, here it's Vcub. Those free bikes you can rent pretty much anywhere.
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What is it like in Bordeaux?

posted October 2013

So, I've been living here for a month and here is my list of what it is to live in Bordeaux.

  • People say "chocolatine" instead of "pain au chocolat" and "poche" instead of "sac". It's kind of weird, especially when I have to say it, I'm always scared that they can tell I'm not from here, which is a stupid thing to be scared of, I had the same kind of feeling when I was living in Canada or China and didn't have the same accent as the locals, but it's weirder having that feeling in my own country.
  • Streets are dirty, really dirty, you will always have to avoid dog poops when you go somewhere. Sidewalks are very small so you also always have to walk directly on the road.
  • The city is pretty small. It's easy to get around. But when something is a bit far, it's annoying to get there since there is no subway.
  • The public transportation system is horrendous, every morning I have to get squished by a thousand students taking the same tramway, most of the time I miss several trams because there are too many people inside, my personal record is seeing five tram passing without being able to enter them. Pretty annoying.
  • Not so much accent here, but people say "gavé" a lot, it means "very". For example "c'était gavé bien hier soir".
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SecureDrop

posted October 2013

SecureDrop is an open-source whistleblower support system, originally written by Aaron Swartz and now run by the Freedom of the Press Foundation. The first instance of this system was named StrongBox and is being run by the New Yorker. To further add to the naming confusion, Aaron Swartz called the system DeadDrop when he wrote the code.
from Schneier's blog

You can find http://deaddrop.github.io/" target="_blank">the website here and if you have something important to submit and do not want to go through Wikileaks, I think this is the best alternative.

The security audit was done by Schneier himself, who is pretty popular in the cryptography community, the work was started by Aaron Swartz who is also extremly popular, especially since his suicide last year.

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New effort to fully audit TrueCrypt raises $16,000+ in a few short weeks

posted October 2013

I just learned that TrueCrypt, the multi-OS solution to encrypt your personal data in a "very easy way" is coded and maintained by ... no one knows. Like bitcoin, the main creators are anonymous. http://www.truecrypt.org/downloads2" target="_blank">The source code is available here but no info about the coders can be found.

It seems like folks are getting a bit worried as TrueCrypt is wildly used, and money is being raised to conduct a security audit on them. http://arstechnica.com/security/2013/10/new-effort-to-fully-audit-truecrypt-raises-over-16000-in-a-few-short-weeks/" target="_blank">More info here.

Now I'm wondering, why is it that those huge cryptographic applications, that are polished and well maintained, are created by anonymous persons? Do they fear they would get pressure from governments? Mafia? Who knows...

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Baidu now accepts bitcoins!

posted October 2013

It's official, http://www.baidu.com" target="_blank">Baidu, the chinese google, now accepts bitcoins.

"As a cutting-edge IT guy and a professional webmaster, what else can showcase our difference? The answer is that we have Bitcoin! Bitcoin, as a new electronic and digital currency, is being accepted internationally. It's also used in daily lives. You can use Bitcoin buy a cup of coffee, or easily convert it to cash. But in China, Bitcoin is still a fairly new thing. Today, we have a good news: from today, we are starting to officially accept Bitcoin as a payment method. You can use Bitcoin to buy all Baidu Jiasule services. Baidu Jiasule as an innovator in the Internet industry, is now the first cloud service provider to accept Bitcoin and give everyone a better payment method and experience."

Read more on https://bitcointalk.org/index.php?topic=310962.0" target="_blank">the bitcointalk about it.

The bitcoin who has been remarkably stable these past weeks, even after the silk road shutdown, has increased a bit more since the announcement.

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Silk Road caught, Tor compromised?

posted October 2013

Silk Road and its owner have just http://www.reuters.com/article/2013/10/02/crime-silkroad-raid-idUSL1N0HS12C20131002" target="_blank">got caught by the FBI. If you didn't know, silk road (an illegal drug market) was hosted on the Tor network as an onion website, which was suppose to grant him total anonymity. Apparently the catch was made from a stupid human mistake :

1) Located the first reference to "silk road" on the internet. You can find this yourself on Google: "silk road" site:shroomery.org Date range: Jan 1,2011 - Jan 31,2011 * 2) The same username, "altoid", showed up on a bitcointalk days later. 3) Later in 2011 "altoid" made a post on bitcointalk with his email address, containing his real name, in it: https://bitcointalk.org/index.php?topic=47811.msg568744#msg5... If you search the name on Google it doesn't show up, but if you look at the user's page you can see it in his posts.

But some are skeptical, and many seems to think it could have been http://www.theguardian.com/world/2013/oct/04/tor-attacks-nsa-users-online-anonymity" target="_blank">the NSA getting into the Tor Network. What do you think?

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RSA-210 has been factored!

posted October 2013

The https://en.wikipedia.org/wiki/RSA_Factoring_Challenge" target="_blank">RSA Factoring Challenge has had one of its entry factored : RSA-210. More info here.

The RSA Factoring Challenge was a challenge put forward by RSA Laboratories on March 18, 1991 to encourage research into computational number theory and the practical difficulty of factoring large integers and cracking RSA keys used in cryptography. They published a list of semiprimes (numbers with exactly two prime factors) known as the RSA numbers, with a cash prize for the successful factorization of some of them. The smallest of them, a 100 decimal digit number called RSA-100 was factored by April 1, 1991, but many of the bigger numbers have still not been factored and are expected to remain unfactored for quite some time.

The challenge is no longer active, this means no money for this brave Ryan P. And this doesn't mean RSA is less secure so no worries :)

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Dread Pirate Roberts response to Atlantis' shutdown

posted September 2013

For someone like me who has some money invested in bitcoins and other cryptocoins (especially litecoin), seeing Atlantis rising (a drug market using litecoin as the main currency) was a very good news. Sadly they had to shutdown months after not doing so much for the https://btc-e.com/exchange/ltc_usd" target="_blank">LTC value.

Here's Silk Road's head statement on the news :

Atlantis was good for Silk Road and the community at large and I am sad to see it go. Yes they were a bit cocky and aggressive, but they never crossed the line and did anything unethical, and they served their customers well. They reminded us in the Silk Road administration that to stay #1, we have to be constantly thinking of our users and how to serve them best and can not take for granted your loyalty. There has been more than one occasion where I have wanted to quit as well. Without going into details, the stress of being DPR is sometimes overwhelming. What keeps me going is the understanding that what we are doing here is more important than my insignificant little life. I believe what we are doing will have rippling effects for generations to come and could be part of a monumental shift in how human beings organize and relate to one another. I have gone through the mental exercise of spending a lifetime in prison and of dying for this cause. I have let the fear pass through me and with clarity commit myself fully to the mission and values outlined in the Silk Road charter. If you haven’t read it yet, please do. Here is the link: “(link omitted)” The bottom line is… Silk Road is here to stay so long as there is breath in my lungs, a spark in my mind, and fire in my heart. I know many of you in this community feel the same way and is an honor to stand beside you here. Lastly, to anyone considering opening another market, you WILL face unexpected challenges one way or another, and if you don’t have the conviction to overcome them then your efforts will likely be in vain. And please open up a dialogue with me if you do open another site. Even competitors can talk from time to time on friendly terms :) Atlantis admins, if you are reading this, I hope you stick around and contribute as you are able.
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