Figure 5: View of WB169-430 module information message received by
WMBUSAN4
analyzer
If the AES-128 data encryption is switched on
, there are two additional
”
control segments” inserted before
data segments of the message. These ”2F” segments serve only for checking of correctness of the decryption. If
using encryption, the total number of data block bytes must be
”
rounded” into integer multiple of 16 Byte (i.e. 16,
32, 48, 64...etc. Bytes). Rounding of the message is performed by inserting of required number of ”2F” blocks.
Decoded encrypted message of the WB169-430 module with two control segments at the beginning and several
other ”2F” blocks at the end is shown in the Figure
. This way the length of message data block is rounded to 64
Byte.
Figure 6: Encrypted and decrypted message of the WB169-430 module
WB169-430
19