USER MANUAL
EMDCB
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BLUETOOTH LOW ENERGY MOTION AND ILLUMINATION SENSOR
© 2019 EnOcean | www.enocean.com
EMDCB User Manual | v1.3 | August 2019 | Page 61/67
B
Authentication example for EMDCB telegrams
We consider the data telegram discussed in chapter A.1 and assume this shall be authenti-
cated by means of a security key known to both the sender and the receiver.
The security key could be obtained in the following way:
◼
From the commissioning telegram as specified in chapter A.2
◼
From the device label as specified in chapter 6.2
◼
From the NFC configuration memory as described in chapter 7
B.1
Input data
The purpose of the security processing is to calculate a unique signature that can be used
to verify authenticity (telegram has not been modified) and originality (telegram comes
from the assumed sender) of a telegram.
The input data for the authentication process is listed in Table 26 below.
Parameter
Comment / Description
Example
Source Address Unique source address of the
sensor module (little endian)
C400000000E5 (little endian rep-
resentation of 0xE500000000C4)
Input Data
Telegram data to be authenticated
15 FF DA 03 57 E2 01 00 02 AA 44
D6 00 45 35 00 20 02
Input Length
Length of input data
(in bytes, encoded using 2 bytes)
0x0015 (21 byte)
Sequence
Counter
Incrementing counter to avoid replay
Part of the input data (byte 4 … 7)
57E20100 (little endian
representation of 0x0001E257)
Security Key
128 bit random key that is known
both to sender and receiver
9E0DE9C25386B6C4F070642E19E03680
Signature from
Sender
32 Bit signature that will be checked
using the security key
C8CC5712
Table 26
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Input data
