MeshMessageSecurity
The mesh message security enum determines authentication level which shall be used when encrypting a segmented mesh message.
This filed is used to determine the TransMIC.
The Message Integrity Check for Transport (TransMIC) is a 32-bit or 64-bit field that authenticates that the Access payload has not been changed.
For a segmented message, where SEG is set to 1, the size of the TransMIC is determined by the value of the SZMIC field in the Lower Transport PDU. For unsegmented messages, SZMIC is 32 bits for data messages.