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USER MANUAL
STM 550B / EMSIB - EASYFIT MULTISENSOR FOR IOT APPLICATIONS (2.4 GHZ BLE)
© 2020 EnOcean | www.enocean.com
F-710-017, V1.0
STM 550B / EMSIB User Manual | v1.3 | June 2020 | Page 111 / 115
B.3
Intermediate parameters
The RFC3610 implementation used in EnOcean BLE products derives four internal parameters
–
Nonce, A0, B0, B1 and B2
–
based on the telegram specific input data and the constant
internal parameters.
These variable internal parameters are described in Table 60 below. The values of these
parameters are calculated based on the input data given in chapter B.1.
Parameter
Comment / Description
Value in the example
Nonce
13 byte initialization vector based on
concatenation of 6 byte little endian source
address, 4 byte little endian sequence
counter and 3 byte 0x00 padding
0000017700E5FB270000000000
A0
A0_Flag
followed by
Nonce
followed by 2
byte
0x00
010000017700E5FB2700000000000000
B0
B0_Flag
followed by
Nonce
followed by 2
byte
0x00
(no message to encode)
490000017700E5FB2700000000000000
B1
Input Length
followed by first 14 byte of
Input Data
00191CFFDA03FB2700000268458D0140
B2
Remaining
Input Data
(up to 16 byte) with
0x00
padding to reach 16 byte in total
420906578AF791E65E23010000000000
Table 60
–
Intermediate parameters