Maxim Integrated Secure Microcontroller - Manual (Page 84)

Secure Microcontroller User’s Guide
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External Circuits
A variety of external circuits can support secure operation. For example, the DS2401 is a unique 48-bit
silicon serial number. If it is installed with the microprocessor, it can be read when the system is first
powered up, then stored inside the secure microcontroller. This serializes the system. If the software ever
finds a different serial number (or missing number) from the stored one, it can refuse to work. This would
mean that the microprocessor had been moved.
Tamper Protection
Using a variety of tamper sensors in conjunction with the DS5002 makes the system very difficult to
crack. These circuits vary from simple switches to light, temperature, pressure, or oxygen sensors. When
the physical security is violated, the SDI pin is activated and the memory contents are destroyed.