New submitter bartvbl writes: As part of the GPL license, D-Link makes its firmware source code available for many of its devices. When looking through the files I accidentally stumbled upon 4 different private keys used for code signing. Only one — the one belonging to D-Link itself — was still valid at the time. I have successfully used this key to sign an executable as D-Link. A Dutch news site published the full story (translated to english with Google Translate).