USER MANUAL
ESRPB / EDRPB - EASYFIT BLUETOOTH® SINGLE / DOUBLE ROCKER PAD
© 2018 EnOcean | www.enocean.com
F-710-017, V1.0
ESRPB / EDRPB User Manual | v1.3 | Jan 2018 | Page 16/68
The receiving device maintains a list of IRK for all transmitters that have been commis-
sioned to work with it.
Whenever the receiving device receives a radio telegram with private resolvable source
address (identified by the most significant bits being set to
0b10
), it will itself generate a 24
bit
hash
from the 24 bit
prand
sequentially using the IRK of each device that it has been
learned into it.
If an IRK matches (i.e. when
prand
is encoded with this specific IRK then the result match-
es
hash
), then the receiver has established the identity of the transmitter.
So conceptually the IRK takes the role of the device source address while
prand
and
hash
provide a mechanism to select the correct IRK among a set of IRK.
This mechanism is illustrated in Figure 12 below.
Figure 12 – Resolving private source addresses
4.5
Check Sum
The 3 byte BLE Check Sum is used to verify data integrity of received BLE radio telegrams.
It is calculated as CRC (cyclic redundancy check) of the BLE Header, Source Address and
Payload fields.