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 39/68
6.7.3
Security Key Write register
The
Security Key Write
register is 16 byte wide and contains the device-unique random
security key.
The factory programmed key can be replaced with a user defined key by following these
steps:
1.
Write new security key into the
Security Key Write
register
Note that for security reasons, setting the Security Key to the following values is not
possible:
0x00000000000000000000000000000000
0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
If the
Security Key Write
register is set to one of these values then no update of
the Security Key will occur.
2.
Set the
Update Security Key
flag in the Configuration register to
0b1
3.
If the key should be write-only (not readable after the key update) then set the
Pri-
vate Security Key
flag in the
Configuration
register to
0b1
4.
Actuate (press and release) one rocker of ESRPB / EDRPB
ExRPB will determine that it should modify the security key based on the setting of the
Up-
date Security Key
flag and copy the value of the
Security Key Write
register to the
Secu-
rity Key
register in private memory.
After successful execution, ExRPB will clear the
Update Security Key
flag to 0b0.
If the
Private Key
flag in the Configuration register is set to
0b0
then the content of the
Security Key Write
register will be maintained at its current value. This addresses use
cases where the security key shall be readable for users having the correct PIN code.
If the
Private Key
flag in the
Configuration
register is set to
0b1
then the content of the
Security Key Write
register will be cleared to
0x00000000000000000000000000000000
after
successful execution. This addresses use cases where the security key shall never be read-
able (even for users having the correct PIN code).
The
Security Key Write
register will maintain this value of
0
x00000000000000000000000000000000
even if the
Private Key
flag in the
Configuration
reg-
ister is subsequently cleared to
0b0.
This ensures that it is not possible to read a security
key which was written with the
Private Key
flag in the
Configuration
register being set.
Note that it is not possible to read the current security key via NFC if the
Security Key
Write
register has been accidentally overwritten or cleared via NFC write. In this case it is
necessary to write a new security key (as described above) or to reset the device to its de-
fault security key by means of a factory reset.
The protected memory is designed to support 1000 modifications of the security key.