ObliqueView posts an interesting series of images of the inside of a Kaba Mas X-09 electronic combination lock (link to manufacturer page and full set). These locks are expensive, but very highly regarded by many locksmiths. At the same time, many old-school locksmiths seem to distrust anything electronic. This seems to have hindered the security analysis of these locks.
I’ve not seen one of these away from a secure filing cabinet. They are very expensive, so this is a nice little insight into their workings. Some quick notes on what I can observe:
- The top of the large (ultra?) cap has been blanked out. I can’t imagine what you would need to hide.
- The pink/orange dots look like UV sensitive ink. This might be for post-intrusion forensics.
- The board has a conformal coating or lacquer. I’m surprised it isn’t fully potted – it would be better for security.
- It looks like a simple two-layer PCB.
- Something odd is going on with the vias. There are a lot of normal small circular vias covered by green solder mask. But a lot are large square, and not covered by solder mask. They might be test points, but that is a lot of them. (edit – I asked on Electronics Stackexchange, without seeding anyone’s mind, what they were – and got test points back. I can only assume because this has to be so reliable, they are into heavy testing)
- Looks like markings on the chips have been removed. This is token. You can identify nearly all processors and chips without markings.
- One of U1 looks like a serial EEPROM, from one side being common and the proximity to the larger chips. It looks like the footprint is designed to take two different sized ICs.
- PCB design is messy, not pleasing to the eye. I can’t work out if this is because it was autorouted, routed by someone inexperienced, or if it is just meant to be confusing to make probing hard.
If anyone has a broken one of these, I’d take it off your hands…