User's Manual

USER MANUAL PREVIEW

PTM 535BZ – BLUETOOTH AND ZIGBEE GREEN POWER PUSHBUTTON TRANSMITTER

D.1.3 Obtaining the security key

All required parameters except the security key can be directly extracted from the received

message that shall be authenticated.

The security key – the common secret shared between sender and receiver – has to be ob-

tained via specific mechanisms.

There are three different ways to obtain the security key used by a PTM 535BZ module

when it is transmitting BLE telegrams:

 Via NFC (by reading SECURITY_KEY1 or by writing SECURITY_KEY2)

 Via the product label (which might provide information about SECURITY_KEY1)

 Via a commissioning telegram as described in Chapter 3.4.3

D.1.4 Internal parameters

The RFC3610 implementation in PTM 535BZ derives a set of internal parameters for further

processing from the provided input parameters.

Again, there are two types of internal parameters:

 Constant internal parameters

These parameters are based on the high-level algorithm and telegram properties and

are the same for any PTM 535BZ telegram

 Variable input parameters

These parameters are based on the telegram-specific parameters and therefore de-

pend on the specifics of the transmitted telegram