User's Manual

SECURE COMMUNICATION (ENCRYPTION)
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TEKs and only one is active at a time. Keyset ID 255
is for KEKs and is considered active all the time
• Each keyset can have up to 128 keys. However, 16
or less are normally used.
• AES encryption is supported (with Flash code 1.8.0
or later) but not currently available with OTAR
(future availability is planned).
RSI (Radio Set Identifier)
• One individual RSI and it is usually initially the
same as the P25 Unit ID.
• One group RSI (usually initially “0”).
• One KMF RSI (usually always 9,999,999).
OTAR Messages That Are Supported
The following KMM Message IDs are recognized
by or sent:
CHANGE RSI 0x03
CHANGE RSI RESPONSE 0x04
KEYSET CHANGEOVER 0x05
KEYSET CHANGEOVER RESPONSE 0x06
DELAYED ACK 0x07
HELLO 0x0C
INVENTORY 0x0D
INVENTORY RESPONSE 0x0E
MODIFY KEY 0x13
MODIFY KEYSET ATTRIBUTES 0x14
MODIFY KEYSET ATTRIBUTES RESPONSE 0x15
NEGATIVE ACK 0x16
NO SERVICE 0x17
REKEY ACK 0x1D
REKEY 0x1E
WARM START 0x20
ZEROIZE 0x21
ZEROIZE RESPONSE 0x22
10.6.2 UCM EQUIPPED 4100
The 41xx UCM version uses the Motorola UCM
encryption module. Therefore, the OTAR capabilities
are determined by that module. All capabilities of the
Motorola KVL and KMF are supported. Initial radio
programming by the PCConfigure software is the
same as described in
Section 10.5.
10.6.3 OTAR OPTION SWITCHES
The following additional option switches can be
programmed with the 4100 portable and 4300 mobile
to control OTAR functions. They are also available as
4100 menu parameters unless noted otherwise.
Change Keyset - Toggles the active keyset between
Keyset 1 and Keyset 2. The new active keyset is
briefly displayed and then normal operation resumes.
When the 4100 menu is used, the current active keyset
is indicated by an asterisk. To change to the other
keyset, highlight it and press the F2 key.
Clear/Secure Select - This enables and disables
encryption regardless of whether OTAR is used. Refer
to Section 10.3 for more information.
Erase Keys - Erases all TEK and KEK keys contained
in the radio. With the 4100, this function is available
as menu parameter only.
Key Select - This allows a different key to be selected
for the current channel or group (conventional chan-
nels only). Refer to Section 10.2.5 for more
information.
OTAR Rekey Request - Sends a message which tells
the KMF that the radio is on the air and requests
rekeying. The following status messages are displayed
which indicate the progress of this function. Addi-
tional functions that are available when this is selected
using the 4100 menu mode are described in the next
section.
Rekeying
- A radio-initiated rekeying session is in
process.
No Ack
- No response was received from the KMF
in response to an Identify request before time out
occurred (approximately 30 seconds).
Ack Rcvd
- An acknowledgement was received in
response to an Identify request.
No Service
- A “No Service” reply was received
from the KMF. No rekeying will take place.