Last week, we had Hackweek at Tor. Instead of doing what we usually do, we worked on small Tor-related projects for 5 days. I chose to work with intrigeri and boyska from Tails to help them improving the pluggable transports on Tails.

There are several ways to get Tor bridges. One is requesting them to BridgeDB through email. The answer contains the bridge lines both as text and in a QR code. So, the first objective of our Hackweek team was to create a proof-of-concept to load these QR codes through a webcam.

Tails’s connection wizard is written in Python. A trivial approach is capturing frames from the webcam with OpenCV, then decoding them with pyzbar. This would have worked, but Tails is a live system, and an OpenCV installation requires a lot of space.

I soon discovered that OpenCV is the de facto way to deal with webcams in Python. I have tried some other alternatives, but they did not work. I have also tried to use a low-level approach based on the V4L2 API. But dealing with the conversion of color spaces and creating a generally reliable solution is burdensome. … [Leggi il resto]