Question

LTE security , ciphering activation time

Answer 1

What is your question

Answer 2

In LTE Security I[1], Part I of the LTE Security technical document, we have discussed LTE authentication based on EPS AKA procedure and learned a UE and an MME get to share the KASMEwhen authenticated.

 

In this document, we will explain NAS and AS security setup procedures to be performed based on KASME, and how data are transmitted in user and control planes after the security setup procedures.

 

Chapter 2 herein will explain NAS security setup procedure and how NAS messages are sent and received after the procedure.

Chapter 3 will cover AS security setup procedure and how RRC messages and IP packets are transmitted thereafter.

Chapter 4 will provide a description of EPS security contexts and security data to be set in EPS entities (UE, eNB, MME and HSS).

Finally, Chapter 5 will summarize all the security keys covered in the LTE Security technical document (LTE Security I and II).

 

Before we move on to security setup procedures, we will look in the protocol stacks where NAS and AS security are actually applied to. Figure 1 shows the protocol stacks related to NAS and AS security setup.