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Each node must support a way to use the following link key types:
1. The default global Trust Center link key (Used by Z-Stack automatically).
2. The distributed security global link key (Used by Z-Stack automatically).
3. An install code derived preconfigured link key (Refer to Z-Stack API to enable set this).
4. The touchlink preconfigured link key (If touchlink enabled).
1. Default global Trust Center link key
All devices share a default global Trust Center Link Key. This is an APS layer key and isthe first key to be used when joining a network, if no other link key is specified. This key cannot be modified if interoperability with other Z3.0 devices is desired.
Default global Trust Center link key (0:15) = 0x5a 0x69 0x67 0x42 0x65 0x65 0x41 0x6c 0x6c 0x69 0x61 0x6e 0x63 0x65 0x30 0x39
2. Distributed security global link key
When a device joins to a distributed security network (no trust center), the network key will be delivered encrypted in APS layer with the Distributed security global link keyby the parent router device. This key cannot be modified if interoperability with other Z3.0 devices is desired.
Distributed Trust Center link key (0:15) = 0xd0 0xd1 0xd2 0xd3 0xd4 0xd5 0xd6 0xd7 0xd8 0xd9 0xda 0xdb 0xdc 0xdd 0xde 0xdf
3. Install Code Derived Trust Center Link Key
An Install Code is a sequence of 16 bytes followed by 2 bytes of CRC. A complete 18 bytes sequence is needed to generate a unique TCLK. The usage of install codes defined in Z3.0 was added to allow a generalized out-of-band key delivery method for network commissioning. It works as follows:
1. TC gets the install code and the 64-bit IEEE address of the device that will use this install code to join, via any user interface (serial, display and switches, etc.).The install code must be physically provided with the joining device.
2. TC validates the CRC of the install code introduced. If this is valid then a TCLK entry is added into the TC with the derived key and the address of the corresponding device.
3. The joining device is instructed to use its install code to generate the corresponding TCLK.
4. The network is open by any means.
5. The joining device performs association and the Trust Center delivers the network key encrypted in APS layer with the install code derived key.
6. After this, the joining device must perform the update of its TCLK as BDB specification requires.
For further details on how to generate the install codes, see the Base Device Specification. This is supported only by R21 or later revisions, soto allow backwards compatibility the application must have a wayto attempt joining networks without the usage of Install Codes.
4. Touchlink preconfigured Link Key
This key is used for development when a device is used to join a network using the Touchlink commissioning procedure.
Touchlink preconfigured link key (0:15) = 0xc0 0xc1 0xc2 0xc3 0xc4 0xc5 0xc6 0xc7 0xc8 0xc9 0xca 0xcb 0xcc 0xcd 0xce 0xcf
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