EnOcean PTM 535BZ, User Manual

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USER MANUAL PREVIEW
PTM 535BZ – BLUETOOTH AND ZIGBEE GREEN POWER PUSHBUTTON TRANSMITTER
© 2021 EnOcean | www.enocean.com F-710-017, V1.0 PTM 535BZ User Manual | v1.0 | May 2021 | Page 25/112
3.4.2.1 Authentication implementation
PTM 535BZ implements data telegram authentication as described in IETF RFC3610
[4] .
The 13 Byte Nonce (number used once – unique) initialization value is constructed as con-
catenation of 6 byte Source Address, 4 byte Sequence Counter and 3 bytes of value
0x00
(for
padding). Note that both Source Address and Sequence Counter use little endian format
(least significant byte first).
Figure 17 below shows the structure of the Nonce.
Figure 17 – Nonce structure
The Nonce and the 128 bit device-unique security key (by default SECURITY_KEY1, alterna-
tively SECURITY_KEY2) are then used to calculate a 32 bit signature of the authenticated
telegram payload shown in
Figure 18 below.
LEN
0x0C
TYPE
0xFF
MANUFACTURER_ID
(Little Endian)
0xDA
SEQUENCE_COUNTER
(Little Endian)
INPUT_STATUS
AUTHENTICATED PAYLOAD
0x03 BYTE0 BYTE1 BYTE2 BYTE3 BYTE0
Figure 18
– Authenticated payload
The calculated 32 bit signature is then appended to the data telegram payload as shown in
Figure 14 in Chapter 3.4.1 .
In addition to the RFC3610 standard
[1] itself, please refer to Appendix D for a step-by-
step description of the authentication process.