An Introduction to 5G

14Security

This chapter covers the security procedures in the 5G system. To help define those procedures, the 3GPP specifications break down the 5G system into a number of different security domains. In previous generations, two of those have been particularly important: network access security, which protects the mobile's communications with the network over the air interface; and network domain security, which protects the network itself. 5G also introduces the concept of service‐based architecture domain security, which protects the network's service‐based interfaces using procedures that are different from the ones used elsewhere.

In this chapter, we will start by reviewing the underlying security techniques that 5G uses, and then work our way through each of its security domains in turn. The most important specification is the stage 2 description, TS 33.501 [1].

14.1 Security Principles

The 5G system is secured using several techniques whose underlying principles are common to all of its security domains. During authentication, two devices confirm that each other is a trusted device, not an intruder, and set up security keys for use by the procedures that follow. Ciphering, also known as encryption, ensures that intruders cannot read the data and signalling messages that two devices exchange.

Some national regulations restrict the use of encryption, which makes two other techniques important. Integrity protection detects any attempt by an intruder to modify the data ...