Ø The SECURITY PROTECTED NAS MESSAGE is sent either by the UE or by the network to transfer a NAS message together with the Sequence Number and the Message Authentication Code (MAC) protecting the NAS message
Ø Once a valid EPS security context exists and taken into use, all the subsequent NAS messages in the uplink or downlink are security protected
Ø The MAC IE contains the integrity protection information for the NAS message
Ø The Sequence Number (SN) IE includes the NAS message sequence number which consists of the eight least significant bits of the NAS COUNT for a security protected NAS message
Ø The IE NAS message includes a complete plain NAS message. The SECURITY PROTECTED NAS MESSAGE and the SERVICE REQUEST message are not plain NAS messages and shall not be included in this IE
Ø The structure of the SECURITY PROTECTED NAS MESSAGE is shown below
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Reference: 3GPP TS 24.301
Example: SECURITY PROTECTED NAS message
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33.401 says "The length of the NAS-MAC is 32 bit" in section "NAS integrity activation"
ReplyDeletebut in 24.008 AUTN => 64 bit MAC.
isn't it contradicting ?
If I have the following message: This analyzer cannot decode this L3 message due to ciphered hex. Is it posible that it can cause a CSFB access failure? When I receive this type of message I get an LDATA CALL DROP followed by an access failure. Thanks.
ReplyDeleteWhat is header type?
ReplyDelete