david wong

Hey! I'm David, the author of the Real-World Cryptography book. I'm a crypto engineer at O(1) Labs on the Mina cryptocurrency, previously I was the security lead for Diem (formerly Libra) at Novi (Facebook), and a security consultant for the Cryptography Services of NCC Group. This is my blog about cryptography and security and other related topics that I find interesting.

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Elliptic Curves posted October 2014

I feel like I don't write much about my formation, and that it could be useful to people who are wondering about studying Cryptography at Bordeaux University.

There is a good article from a M1 student here: http://journaldumaster.stats.yt/master-csi-presentation/

And as it says there, the master 1 is do-able both for maths and CS people as long as you're willing to catch up in the other subject. There's a lot of theory that will allow you to study more interesting subjects in the second year of Master.

I've talked about some of the subjects but one subject I forgot to talk about was a M1 class: Elliptic Curves, taught by Fabien Pazuki and if you have the chance of taking a class from the guy just do it. He's one of the best math teacher I have had in my life, along with Vincent Borrelli (Surfaces & Curves at Lyon 1) and some dude I can't remember the name of. Each one of them were both really passionate and making true efforts to be pedagogical.

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Hack of the Day: How do I run untrusted shell code? posted October 2014

I've run into a nice series of video called "hack of the day" from Vivek-Ramachandran.

In this first video he explains two techniques :

  • jump-call-pop
  • xor decoding

I also got nice tips like the examining string function in gdb : x/s $ebx or the folder usr/include/asm that contains plenty of information about assembly.

The full playlist can be found on securitytube.net

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POODLE: new attack on SSL posted October 2014

A new attack on SSL 3.0 has been discovered. It's relevant because most browsers (except for Opera) allow a downgrade to SSL 3.0 if it cannot seem to use newer versions. Of course an attacker could disturb the connection and force someone to use SSL 3.0 in order to use the POODLE attack.

Full and clear explanation here

You might want a reminder of what is CBC to read it:

CBC

tl;dr: attack happens because of the way padding works in CBC in SSL 3.0

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Erasmus & Korean posted October 2014

A new year starting means new erasmus coming. And this year I've done things a bit differently, instead of just meeting the newcomers I've joined the Erasmus association of Bordeaux "Inter'action Bordeaux" and I've helped them organized many events. Parties of course but also some really cool stuff like:

  • A welcome erasmus week-end in a camping next to the Sanguinet lake (and for the first time of my life I slept on the beach! Not really comfy).

sanguinet lake erasmus week end interaction bordeaux

sanguinet lake erasmus week end interaction bordeaux

  • The Feria of Bordeaux, and no worries, no animals were injured, it was more like a silly cow running around people :)

feria bordeaux

feria victoire

Aside from participating in this new adventure, I've also started taking Korean classes at the same place where I was taking russian classes last year. And I already learned how to write/read korean. It's actually not that hard at all and if you have a few hours to spare you could learn it too :)

korean

I forgot that I also spent quite some time learning Romanian on Memrise this summer and I fell in love with Memrise again. I was actually the first of many romanian classes rankings for many weeks.

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