I am trying to prevent a potential attack, by first learning how to perform it.
Pretend there is a cheap £20 - £50 computer, which an attacker with physical access to wishes to crash. This computer will remain plugged into the power (electric going through it), but must be crashed (as in not working while the attacker is attacking it).
This attack will be short to medium term, so highest 2 months at a time. It must not cause permanent damage, as much as possible.
The attacker is limited as it is protected by a plastic case, good locks, and various anti tamper protection. However, the gap between the circuits and plastic is only a few centimeters. We have no way of preventing anyone getting physical access.
Must be as easy, cheap, less technical, and safe as possible. No use recommending something which has a long distance so exposes humans or other computers which are nearby. But they will very rarely be within a meter of the device, the device could be pointed in the direction of the computer attached to the front of the plastic case, and put in a lead box to stop leakage?
With the above in mind - what would be the best way to achieve this? EMP, but would that not damage computer? Xrays? Any ideas are welcome.
Please note: we only want physical attacks at the moment, such as using waves. No software attacks, nor hacking WiFi etc... this is to crash the computer, think of this like crashing a calculator (except more powerful).
EDIT: Think of the device like an electric "smart" meter. That shape, cost, design, hardware, almost similar security.