USER MANUAL
PTM 216Z – 2.4 GHz Zigbee Generic Switch Pushbutton Transmitter Module
© 2018 EnOcean | www.enocean.com
F-710-017, V1.0
PTM 216Z User Manual | v1.2 | November 2018 | Page 18/43
4.2
Algorithm parameters
PTM 216Z implements telegram authentication according to the Zigbee Green Power speci-
fication. It uses AES128 in CCM (Counter with CBC-MAC) mode as described in IETF
RFC3610. At the time of writing, the RFC3610 standard could be found here:
https://www.ietf.org/rfc/rfc3610.txt
The 13 Byte CCM Nonce (number used once – unique) initialization value is constructed as
concatenation of 4 byte Device ID, 4 byte Device ID again, 4 byte Sequence Counter and 1
status byte of value 0x05.
Note that both Device ID and Sequence Counter use little endian format (least significant
byte first). Figure 11 below shows the structure of the AES128 Nonce.
Figure 11 – AES128 Nonce structure
The AES128 Nonce and the 128 bit device-unique security key are then used to calculate a
32 bit signature of the authenticated telegram payload for data and decommissioning tele-
grams.
The authenticated data for data telegrams is shown in Figure 12 below.
Figure 12 – Authenticated payload for data telegrams
The authenticated data for decommissioning telegrams is shown in Figure 13 below.
Figure 13 – Authenticated payload for decommissioning telegrams
The calculated 32 bit signature is then appended to the data telegram payload as shown in
chapter 3.3.
The security key required for the telegram authentication can be obtained from the product
DMC code as shown in chapter 6.3.1. For Zigbee Green Power receivers, it is also provided
as part of the commissioning telegram as described in chapter 3.3.2.