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The terminal supports loading of the keys via a Key Variable Loader (KVL) tool.
By using a special secret key combination it is possible for a user to delete the cipher keys in the
terminal. This can be provisioned to erase either all keys or only the long-term keys.
12.3.7
User Key Deletion
User can delete Encryption & / or Authentication keys by a special sequence from the keypad.
The key deletion key sequence is: Side Button 1, Side Button 1, Side Button 1, Side Button 2, Side
Button 2, Side Button 2.
Benefits:
•
This allows user to clear the keys for example for transit.
12.4
Terminal Disable/Enable
Terminal disable using TETRA Temporary Disable is supported.
Upon reception of an appropriate TETRA signalling for "Subscription Disable" with the correct SSI
and MNI of the terminal, the terminal will be disabled. Also if the encryption keys are erased, the
terminal will put itself in the disabled state.
When disabled, the terminal will not participate in any voice call, SDS nor packet data activity and
will ignore all Supplementary Services sent on the downlink. All visible and audible indications will
be disabled, and the terminal will appear to be powered off. All user inputs (key presses, knob
operation) will be ignored, and the PEI interface will be closed.
The terminal can be provisioned to show the user a message upon becoming disabled.
The terminal will continue to perform Mobility Management functions, such as roaming, in order to
facilitate subsequent enabling (or further disabling) of the terminal.
The terminal will store the disabled/enabled state in the codeplug, such that if the unit is powered
down and subsequently powered up it will remain in that state.
If the terminal is in the disabled state, and receives an appropriate TETRA signalling with the correct
SSI and MNI of the terminal, the terminal will be restored to its normal operative state.
Upon reception of an appropriate TETRA signalling for "Equipment Disable" with the correct TEI for
this terminal, the terminal will be disabled.
If the terminal is in the equipment disabled state, and receives an appropriate TETRA signalling with
the correct TEI (in the case of equipment disable), the terminal will be restored to its normal
operative state (provided that the subscription is also in the enabled state).
12.5
Terminal Permanent Disable
Permanent disabling is intended to protect a network from attack from a compromised or faulty
terminal. It can be used when the terminal is known to have been compromised, or has been
suspected of compromise for a long time.
It is a one way function, there is no equivalent enable. The terminal would need to be recovered and
reprogrammed before it could be used again.
When the terminal is permanently disabled, it becomes inoperable:
•
All its security key material, that is GCK, GSKO, DMO SCKs, Ks, DCK, CCK, TMO SCKs are
deleted.
•
All its Codeplug is deleted.
6866588D21-D
Chapter 2 - MTP850 Ex/MTP810 Ex Product Information Manual
Services and Feature Description
March 2009
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