Decoding TS24301Msg_PDU

The procedure for decoding TS24301Msg_PDU is basically the same as given above. When the encoded message is security protected, however, there are a few additional requirements. These steps are not necessary when decoding a message without security protection (but, unless you are certain the message is not security protected, you will need to follow these requirements).

For security protected messages, including SERVICE REQUEST messages (which always have integrity protection):

  1. Initialize the NAS security context

  2. Specify the algorithm and keys to use

  3. Set NAS security parameters

  4. Free the NAS security context when finished.

Each of these steps is illustrated in the encoding example above. The NASDec_TS24301Msg_PDU function will: