cjsatuforc / gr-keyfob

Transceiver for Hella wireless car key fobs.

This is a GNU Radio module to receive and reencode signals of (some) wireless car key fobs from Hella.

Dependencies

GNU Radio v3.7.X or the v3.8 development branch (next)

Installation

mkdir build
cd build
cmake ..
make
sudo make install
sudo ldconfig

Usage

See the flow graphs in the apps folder.

Frame Format and Crypto

I recommend checking out the paper Lock It and Still Lose It – On the (In)Security of Automotive Remote Keyless Entry Systems by Flavio D. Garcia, David Oswald, Timo Kasper and Pierre Pavlidès, presented at the 25th USENIX Security Symposium.

The paper covers the frame format, crypto, and security issues of wireless key systems. This transceiver supports what the authors call VW-3 and VW-4. According to my understanding, the WAV files (i.e., signal samples) in this repository and a firmware dump of the ECU should be a good starting point to clone key fobs and to extract the master key.

There is also a Wired article on it.

Further Information

I blogged about the module and gave a talk at SDR Academy (slides and video).