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USER MANUAL
EMDCB
–
BLUETOOTH LOW ENERGY MOTION AND ILLUMINATION SENSOR
© 2019 EnOcean | www.enocean.com
EMDCB User Manual | v1.3 | August 2019 | Page 66/67
C
Address resolution for resolvable private addresses (RPA)
EMDCB provides the option to obfuscate its identity by means of using resolvable private
addresses (RPA) as described in chapter 4.4.2. The following chapters describe how to re-
solve such addresses.
C.1
RPA resolution flow
The execution flow for resolving private addresses (RPA) is shown in Figure 38 below.
Figure 38
–
Execution flow for resolving private addresses (RPA resolution)
The input to the RPA resolution flow are the
prand
part of the resolvable private address
field of the received telegram together with one (or several) locally stored IRK.
The receiver will then try for each locally stored IRK if the
hash
generated using the execu-
tion flow above matches the
hash
part of the resolvable private address field of the received
telegram. If it does then the IRK identifies the device from which this telegram originated.
C.2
Obtaining the IRK
EMDCB uses its device-unique random private security key as IRK. This key is programmed
at manufacturing and can be changed via the NFC interface as described in chapter 7.6.6.
The IRK could be obtained in the following way:
◼
From the commissioning telegram as specified in chapter A.2
◼
From the NFC configuration memory as described in chapter 7
◼
From the device label as specified in chapter 6.2 (if the factory-programmed securi-
ty key has not been changed via the NFC Interface)
0000000...0000000
prand
104 Bit Padding (all zero)
24 Bit prand
Identity Resolution Key (IRK)
128 Bit Identity Resolution Key (IRK)
AES128
Don
t Care
hash
104 Bit Don
t Care
24 Bit hash