Digi XBee 3 Cellular LTE-M User Manual page 269

API frames
Frame data fields
Step
Payload
The tables below give more information about the phase of authentication and interpretation of
payload data.
Phase 1 (Client presents A)
If the A value is zero, the server will terminate the connection.
Frame data field
A
Phase 2 (Server presents B and salt)
Frame data field
salt
B
Phase 3 (Client presents M1)
Frame data field
M1
Digi XBee® 3 Cellular LTE-M/NB-IoT Global Smart Modem User Guide
Offset Description
4 Indicates the phase of authentication and interpretation of payload
data. See
1 = Client presents A value
2 = Server presents B and salt
3 = Client present M1 session key validation value
4 = Server presents M2 session key validation value and two 12-
byte nonces
See the phase tables
Step values greater than 0x80 indicate error conditions.
0x80 = Unable to offer B (cryptographic error with content, usually
due to A mod N == 0)
0x81 = Incorrect payload length
0x82 = Bad proof of key
0x83 = Resource allocation error
0x84 = Request contained a step not in the correct sequence
5 Payload structure varies by Frame ID value. Descriptions are in the
tables, below.
Offset in frame
5
Offset in frame
5
9
Offset in frame
5
BLE Unlock API - 0x2C
below for more information.
Length
128 bytes
Length
4 bytes
128 bytes
Length
Hash algorithm digest length
(32 bytes for SHA256)
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