That works against you. With the hollow devices, you can weigh it to see if there’s a difference.

If it’s full of glue, remove glue, add your implant and add enough counterweight so it weighs the same as the stock device.

> remove glue

It's supposed to be "potting compound", which is a form of epoxy, and if the right one is chosen it's very hard to get it off with anything short of fuming nitric acid. Combined with the microwires trick it can be made extremely difficult to get at the PCB without triggering the tamper detection.

See FIPS 140: https://webcache.googleusercontent.com/search?q=cache:HERKv5... (google cache version because the US has decided to be a failed state for a few weeks again)

Thanks for that info. These devices are FIPS certified so I'd expect you've explained exactly what it was.

Interesting trade off. I can't see many people in practice weighing a device. I could see a casual hacker physically destroying a device putting such an implant in. But not every attacker or victim are in the common category.

Of course, getting there earlier in the supply chain..

Should be par for the course for individuals putting their life savings on such a thing. A kitchen scale gives you .1g accuracy, which should be enough to tell you something is off.

I've heard the same for fake IDs: clubs will weigh them to see if their weight is within range of real IDs.