Doc. No: Unex-QSG-21-003
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cannot move back to the testing mode.
The source and trigger mode of tamper detection signal can be selected with the DIP
switch on SOM-352, position SW1.6 and SW1.7.
Tamper detection pins are exposed in both mPCIe interface pin 51 and I/O cable pin 6.
Pulling the tamper detection pin to ground will trigger a tamper event, indicating that the
enclosure of the system has been opened without proper authorization. User can enable
one of the two tamper modes in API:
1
Production mode
2
Test mode.
9.10.1.
Production Mode
In production mode, the SOM-352 will erase the CSP (critical security parameter)
material saved in eHSM. The eHSM hardware will be left unusable because the CSP
cannot be rewritten to the chip anymore. Two additional tamper modes are available when
entering production mode: normal mode and standby mode.
9.10.1.1.
Normal Mode
Tamper response provides protection against tamper attempts during operational state
when the chip is powered on. When it is enabled, tamper event will immediately trigger the
zeroization sequence. Enabling this mode is done by invoking the Enable Normal mode
tamper response service API.
9.10.1.2.
Standby Mode
Tamper response provides protection against tamper attempts while the chip is in sleep
mode state. When it is enabled, any previously latched tamper event during sleep mode
will trigger the zeroization sequence upon power-up. Enabling this mode is done by
invoking the Enable standby mode tamper response service API.
9.10.2.
Test Mode
In test mode, the SOM-352 will not erase the CSP (critical security parameter) material
saved in eHSM. Each invocation of the tamper signal increments an internal counter within
the eHSM. This counter can then be inquired by calling the eHSM runtime status API,