25-3.1.3 Key Type
An encryption key is needed when testing in the
encryption mode. There are two encryption key
types that can be selected, either a Test Key or an
External Key. The Test Key is the default and is
used to support most Project 25 testing. The Test
Key is a predefined key that is programmed into
the analyzer for testing purposes only. In order to
prevent compromised security, the Test Key
should never be used for sending secure radio
communications (all Project 25 analyzers use the
same Test Key). The External Key is a key that
has been loaded from a KVL. In order to test
secure communications the keys in both the Unit
Under Test and the analyzer must be the same.
The analyzer provides these softkey selections:
TEST KEY
This softkey selects the Test Key saved in the
analyzer's key storage memory.
EXT KEY
This softkey selects the External Key saved in the
analyzer’s storage memory for the selected
algorithm. This key is defined by the customer
and must first be loaded into the analyzer by a
KVL.
erase ext key
This softkey erases from the analyzer’s key
storage memory any External Key saved for
the current algorithm.
load ext key
This softkey starts the sequence of
programming the analyzer with an External
Key for the algorithm selected from a Key
Variable Loader (KVL). This procedure
requires a key loading cable and KVL.
25-3.1.4 Encrypt Self Test
A self test of the encryption functions is
performed at power up. The “Encrypt Self Test:”
field in the SET UP display (Figure 25-2)
indicates the results of the self test, passed or
failed.
25-3.2 Using the Test Key
The analyzer can be used to test radios using the
internal Test Key (707070….hex). To select the
Test Key, place the cursor in the “Display:” field
in the Display Zone. Select SET UP using the
SET UP softkey. This will access the SET UP
display screen (Figure 25-2).
Move the cursor to the “Encrypt:” field and select
the ON softkey (Figure 25-3). Move the cursor to
the "Algorithm Sel:" field and select the desired
algorithm using softkeys (Figure 25-4). Move
cursor to the "Key Type:" field and select the
TEST KEY softkey (Figure 25-5). The analyzer
is now programmed with the Test Key.
Project 25 radios also have an internal Test Key
which is the same as the analyzer’s. Refer to the
radio service manual to determine if this key can
be activated in your particular radio. If the
internal Test Key cannot be activated, it must be
loaded from a KVL.
Follow the procedure in the KVL instruction
manual to load the 707070…..hex key into the
radio. The radio encrypter is now keyed to match
the analyzer.
25-3.3 Programming with External Key
You can use a custom
er key to program the
analyzer and operate in private mode with a
keyed radio. The customer (external) key, once
loaded, is saved in memory by the analyzer until
the operator erases it. The key is stored in non-
volatile memory and will be retained even if
power to the analyzer is turned off.
25-3.3.1 Connecting the KVL
The KVL plugs into the KVL port (Figure 23-1)
on the side of the analyzer opposite the carrying
handle. Connect the KVL to the analyzer and
then use the following instructions to load the
External Key.
309
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