Today, in order to exclude the theft of cryptographic keys by spyware, they are placed in so-called hardware protected modules. They represent a container, inside the walls of which, with a micrometer pitch, a network of live wires filled with resin is laid. It does not react to shocks and falls, but it is worth breaking through the outer shell and reaching the network, as an open circuit or short circuit occurs. The sensors will automatically give the command to erase the keys on the board inside the module - the burglar will receive nothing.
The technology is simple, but it has more than enough disadvantages, and most boil down to dependence on an external source of energy. If you disable it and try to bypass the security system, the information inside the container is automatically erased. But the same will happen with a banal wire breakage or damage to the battery itself, for example, in an earthquake or fire. And if you transport a module with a battery at low temperatures, it will discharge faster than the valuable cargo reaches its destination.
The Fraunhofer Institute (Germany) has proposed a new version of the protected hardware module - the non-volatile B-Trepid. The idea is not to constantly check the parameters of the electrical shell of the container, but to read them when accessing the keys. For this, the same wire mesh is created, but with an individual architecture and, as a result, unique capacitance parameters. At the first connection, this parameter is written into the memory of the checking unit, and if later the container is damaged, when activated, the check will reveal this and give the command to erase the key. The rest of the time the system is de-energized and safe.
German engineers claim to have learned how to make containers with a unique "electrical signature" that cannot be copied and reproduced. The container itself is the key, and if you use it to encrypt the protected cryptographic data, then it becomes pointless to break the module itself. Even a hole with a diameter of 0.3 mm already violates its structure and puts everything out of action - a potential thief will have to act extremely delicately.