Radio Disable/Enable; Radio Permanent Disable - Motorola MTP850 S Product Information Manual

• SIM interface encryption and authentication using the AES.
The file system holds the following.
• Network access parameters as ITSI.
• Security class definition and authentication definition.
• Integrated circuit card identifier.
• SIM version number.
• Operative Tactical Address (OPTA).
The E2EE keys are also kept on the SIM. However, they are accessible for the SIM application only, thus E2EE key
management is transparent to the radio.
The keys for AIE remain on the radio. The SIM application handles AIE key management.

Radio Disable/Enable

A dispatcher can disable or enable the radio remotely.
When disabled, the radio does not participate in any voice call, SDS, or packet data activity and ignores all
supplementary services sent on the downlink. All visible and audible indications are disabled, and the radio appears to
be turned off. All user inputs (key presses, knob operation) are ignored, and the PEI interface is closed.
The radio continues to perform mobility management functions, such as roaming, to facilitate subsequent enabling (or
further disabling).
The radio stores the disabled/enabled state in the codeplug, so the unit remains in that state after turning on.
If the radio is in the disabled state, and receives an appropriate TETRA signaling for subscription enablement with the
correct SSI and MNI, it restores to its normal operative state.
The TEI Query feature provides TEI information to the infrastructure during registration. This allows to disable the
radio by sending an appropriate TETRA signaling for equipment disable with the correct TEI for this radio. Replacing
the SIM card does not activate the radio.
If the radio is in the equipment disabled state, and receives an appropriate TETRA signaling with the correct TEI, the
radio restores to its normal operative state (if the subscription is also in the enabled state).

Radio Permanent Disable

Permanent disabling is intended to protect a network from attack from a compromised or faulty radio. It can be used
when the radio has been compromised, or has been suspected of compromise for a long time. It is a one-way function
and no equivalent enable is available. Then the radio should be recovered and reprogrammed before being used again
by the service provider.
When the radio is permanently disabled, it becomes inoperable.
• All its MMI interfaces on the radio are disabled.
• All its security key material, that is GCK, GSKO, DMO SCKs, Ks, DCK, CCK, TMO SCKs are deleted.
• All its codeplug is deleted.
• All its software is deleted.
The permanent disable should be invoked when it has been determined that a radio is unrecoverable. When a radio
has been lost or stolen, the first step always is to stun the radio (using the temporary disable).
The permanent disable should be used with the deletion of the user radio record in the User Configuration Server and
the deletion of the K-REF association of the disabled radio in the Provisioning Centre and the Authentication Centre.
This deletion ensures that subscriber information is not downloaded into the Home Location Register if a restore of
the UCS is performed.
The system operator has to also ensure that the radio K-REF association is also removed from the other
Authentication Centres in the network, in cases where the K-REF pairs are duplicated across the network.
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