Cryptoprocessjoinaccept; Table 10-6: Cryptoprocessjoinaccept Command; Table 10-7: Cryptoprocessjoinaccept Response - Semtech LR1121 User Manual

10.3.4 CryptoProcessJoinAccept

Command CryptoProcessJoinAccept(...) decrypts the join accept message (using AES-ECB encrypt as per
LoRaWAN specification) on the Data and Header, and then verifies the MIC of the decrypted message.
The decrypted data is then provided, if the MIC verification is successful.

Table 10-6: CryptoProcessJoinAccept Command

Byte 0
Data from Host 0x05
Data to Host Stat1

Table 10-7: CryptoProcessJoinAccept Response

Byte
Data from Host 0x00
Data to Host Stat1
• DecKeyID and VerKeyID are defined in
DecKeyID: Key used for decryption of the message.

VerKeyID: Key used for MIC verification.

• LoRaWANVer: Determines the expected Header size N: 1 byte (v1.0) or 12 bytes (v1.1).
LoRaWANVer=0: LoRaWAN version 1.0.x, only MHDR (1 byte).

LoRaWANVer=1: LoRaWAN version 1.1.x, SIntKey, JoinReqType | JoinEUI | DevNonce | MHDR.

• Header1 to HeaderN: Header. N depends on LoRaWANVer.
• Data1 to DataM: Data. Data size M is either 16 or 32 bytes. Data must include the encrypted MIC.
• CEStatus is defined in section
LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
1 2 3
DecKeyID VerKeyID
0x04
(7:0) (7:0)
IrqStatus IrqStatus
Stat2
(31:24) (23:16)
0 1
0x00
CEStatus
Table 10-1: Cryptographic Keys Usage and
CEStatus on page
www.semtech.com
4 5
LoRa
WANVer Header1
(7:0)
IrqStatus IrqStatus
(15:8) (7:0)
2
0x00
Data1
103.
... N+4 N+5
... HeaderN Data1
... 0x00 0x00
...
...
...
Derivation:
Proprietary & Confidential
... N+4+M
... DataM
... 0x00
M+1
0x00
DataM
105 of 130
Semtech