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Abstract
The Selective Radio Inhibit feature allows the CentraVBasestation operator to send a message to a radio that prevents further use of the radio until it receives a subsequent "uninhibit" message, or until certain non- volatile memory contents can be restored by an author- ized service center. Certain measures are presently implemented to prevent unauthorized activation of inhibited radios, especially for radios with Secure capa- bilities. It may be desirable, however, to provide an addi- tional measure of security.
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MOTOROLA INC. Technical Developments Volume 15 May 1992
TIMESTAMPED UNINHIBIT MESSAGE
by Charles I? Schultz
The Selective Radio Inhibit feature allows the CentraVBasestation operator to send a message to a radio that prevents further use of the radio until it receives a subsequent "uninhibit" message, or until certain non- volatile memory contents can be restored by an author- ized service center. Certain measures are presently implemented to prevent unauthorized activation of inhibited radios, especially for radios with Secure capa- bilities. It may be desirable, however, to provide an addi- tional measure of security.
When a Secure radio receives a "radio inhibit" com- mand it may also be programmed to destroy any key information stored within its non-volatile memory (key destruct on inhibit). This prevents a hostile party from having Secure capabilities if they are able to restore the non-volatile memory to the uninhibited state.
Radios with multiple key capabilities normally keep a key-loss key so that encrypted commands may still be received if keys are accidentally lost. Intentional destruc- tion of keys (zeroizing) causes the key-loss key to be lost as well. Multiple key radios do not normally pro- vide "key destruct on inhibit" because they are concerned
about hostile parties using playback of recorded uninhibit messages to restore the radio. By leaving the keys intact, a properly encrypted message is required for uninhibiting. This has the drawback, however, of providing a Secure radio to those p...
