A great FAQ, written by Marc Joye (Thomson R&D), on Whitebox Cryptography.
Thansk Tancrède for the link!
Q1: What is white-box cryptography?
A major issue when dealing with security programs is the protection of "sensitive" (secret, confidential or private) data embedded in the code. The usual solution consists in encrypting the data but the legitimate user needs to get access to the decryption key, which also needs to be protected. This is even more challenging in a software-only solution, running on a non-trusted host.
White-box cryptography is aimed at protecting secret keys from being disclosed in a software implementation. In such a context, it is assumed that the attacker (usually a "legitimate" user or malicious software) may also control the execution environment. This is in contrast with the more traditional security model where the attacker is only given a black-box access (i.e., inputs/outputs) to the cryptographic algorithm under consideration.
Q2: What is the difference with code obfuscation?
Related and complementary techniques for protecting software implementations but with different security goals include code obfuscation and software tamper-resistance. Code obfuscation is aimed at protecting against the reverse engineering of a (cryptographic) algorithm while
software tamper-resistance is aimed at protecting against modifications of the code.
All these techniques have however in common that the resulting implementation must remain directly executable.
Or as Francis Gabriel writes here
Code obfuscation means code protection. A piece of code which is obfuscated is modified in order to be harder to understand. As example, it is often used in DRM (Digital Rights Management) software to protect multimedia content by hiding secrets informations like algorithms and encryption keys.
SECURITY DAY will take place at the University of Lille 1, in France, on January 16th. People from Quarkslab (where I almost did my internship), ANSSI, Microsoft, ... will give talks. There is even one of my classmate Jonathan Salwan.
I'm trying to find a way to get there, so if you want to buy me a beer this might be the right place :D
As requested, I added a rss feed to this blog. It's available here in markdown, and here in html, choose whichever suits you best.
posted December 2014
I like how people make an extreme effort to create "sure" source of random numbers.
OneRNG has released a new usb source. Everything is opensource (open hardware, open software), you can even create your own by following instructions on their websites.
OneRNG collects entropy from an avalanche diode circuit, and from a channel-hopping RF receiver. It even has a “tinfoil hat” to prevent RF interference — you can remove the hat in order to visually verify the components being used.
Now I'm wondering who is using that and for what
High on Coffee has released a cheatsheet on nmap. Full of examples and tips. You can find it here
EDIT: There are also Linux Commands for Penetration Testers there. The blog seems pretty new and it already has really good content :)
A new vulnerability has been discovered on the git client. See Github's announcement
Repositories hosted on github.com cannot contain any of the malicious trees that trigger the vulnerability because we now verify and block these trees on push.
The official announcement and the updated and fixed version of git is here.
We used to allow committing a path ".Git/config" with Git that is
running on a case sensitive filesystem, but an attempt to check out
such a path with Git that runs on a case insensitive filesystem
would have clobbered ".git/config", which is definitely not what
the user would have expected. Git now prevents you from tracking
a path with ".Git" (in any case combination) as a path component.
More information about the vulnerability here
Git maintains various meta-information for its repository in files in .git/ directory located at the root of the working tree. The system does not allow a file in that directory (e.g. .git/config) to be committed in the history of the project, or checked out to the working tree from the project. Otherwise, an unsuspecting user can run git pull from an innocuous-looking-but-malicious repository and have the meta-information in her repository overwritten, or executable hooks installed by the owner of that repository she pulled from (i.e. an attacker).
And I just passed the last exam of this semester, which should be the last exam of my life =)
Now is time to take a few days to relax and eat nice food because it will soon be christmas ^^ (or holidays, as I heard some american say to avoid saying christmas).
A few interesting things I had to do during my exams these last few days:
- Simple Power Analysis (SPA). Guess what algorithm is used from smartcards' traces and calculate the exponent if it's a binary exponentiation
In the picture you can see two patterns, "1" is represented by two operations in the algorithm, and one of them is squaring which happens also when you have a "0" in your exponent's binary representation. So following the computations revealed by the power trace you can guess the binary representation of the exponent.
I had to read this article explaining two malloc implementations and their vulnerabilities. GNU Lib C (used in Linux) and System V AT&T (used in Solaris, IRIX). I knew the double chained list system but System V uses a different approach: binary tree and also a
realfree function that completes the
Josip Franjković found a vulnerability in one of the file uploader of facebook.
He described what he did here
basically he uploaded a zipped file of a symbolic link to
ln -s /etc/passwd link
zip --symlinks test.zip link
And since uploaders are always a mess to secure. Facebook just replied displaying the content of what he thought was the unzipped resume.