USER MANUAL
PTM 215B – BLUETOOTH
®
PUSHBUTTON TRANSMITTER MODULE
© 2019 EnOcean | www.enocean.com
F-710-017, V1.0
PTM 215B User Manual | v1.9 | June 2019 | Page 79/85
C.1.5
Constant internal parameters
The RFC3610 implementation in PTM 215B derives two internal parameters – M’ and L’ –
based on the input data and uses them to construct A0_Flag and B_0_Flag which – togeth-
er with the iteration counter i – are required for subsequent processing.
The value of these internal parameters - listed in Table 12 below - is the same for all PTM
215B telegrams.
Parameter
Comment / Description
Example
M’
Binary encoded output length
M’ = (Output length / 2)
- 1
0b001
(always)
L’
Binary encoded length field size
L’ = length field size
- 1
0b001
(always)
A0_Flag
L’
0x01
(always)
B0_Flag
(0b01<<6) +
(M’<<3) + L’
0x49
(always)
i
Iteration counter
0x0000 (always)
Table 12 – Constant internal parameters
C.1.6
Variable internal parameters
The RFC3610 implementation in PTM 215B derives four internal parameters – Nonce, A0,
B0 and B1 – based on the telegram specific input data and the constant internal parame-
ters.
These variable internal parameters - listed in Table 13 below - are then used together with
the security key to calculate the actual signature.
Parameter
Comment / Description
Example
Nonce
13 byte initialization vector based on
concatenation of source address, sequence
counter and padding, see 4.7.1
FE19000015E2D00A0000000000
A0
A0_Flag
followed by
Nonce
followed by 2 byte
0x00
01FE19000015E2D00A00000000000000
B0
B0_Flag
followed by
Nonce
followed by 2 byte
0x00
(no message to encode)
49FE19000015E2D00A00000000000000
B1
Input Length
followed by I
nput Data
fol-
lowed by 5 / 4 / 3 / 1 byte of
0x00
padding
(for optional data size = 0 / 1 / 2 / 4 byte)
00090CFFDA03D00A0000030000000000
Table 13 – Variable internal parameters
