Over at my personal site I’ve just announced the release of a Python script to generate the keys used to digitally re-sign Xbox saves.
Using xbox-save-sig is as simple as passing in the path to a default.xbe file:
python xboxsig.py -i /path/to/default.xbe
The output will be a text representation of the digital signature for save signing:
The script can output the key in a selection of formats and being Python can run on many different systems.
The script is licensed under the MIT License, which is pretty permissive, so feel free to fork, improve and put it to good use!