Digi XBee3 XB3M1, Руководство пользователя

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API frames BLE Unlock API - 0x2C
Digi XBee3 Cellular LTE-M/NB-IoT Global Smart Modem User Guide 230
Phase 4 (Server presents M2)
Frame data field Offset in frame Length
M2 5 Hash algorithm digest length
(32 bytes for SHA256)
TX nonce 37 12-byte (96-bit) random nonce,
used as the constant prefix of
the counter block for
encryption/decryption of data
transmitted to the API service
by the client
RX nonce 49 12-byte (96-bit) random nonce,
used as the constant prefix of
the counter block for
encryption/decryption of data
received by the client from the
API service
Upon completion of M2 verification, the session key has been determined to be correct and the API
service is unlocked and will allow additional API frames to be used. Content from this point will be
encrypted using AES-256-CTR with the following parameters:
n
Key : The entire 32-byte session key.
n
Counter : 128 bits total, prefixed with the appropriate nonce shared during authentication.
Initial remaining counter value is 1.
The counter for data sent into the XBee API Service is prefixed with the TX nonce value (see the
Phase 4 table, above), and the counter for data sent by the XBee to the client is prefixed with
the RX nonce value.
Example sequence to perform AT Command XBee API frames over
BLE
1. Discover the XBee3 device through scanning for advertisements.
2. Create a connection to the GATT Server.
3. Optional, but recommended, request a larger MTU for the GATT connection.
4. Turn on indications for the API Response characteristic.
5. Perform unlock procedure using unlock frames. See BLE Unlock API - 0x2C .