When a credit card is swiped, the bank card authentication message displayed is for the bank to verify whether the user has the right to access the system. Authentication is to verify whether the user has the right to access the system. The mainstream authentication method is to use authentication authorization to verify whether the digital signature is correct or not.

Authentication includes two aspects:

1. User authentication. The network authenticates users to prevent illegal users from occupying network resources.

2. Network authentication. Users authenticate the network to prevent users from accessing illegal networks and being defrauded of key information.

Authentication includes two aspects

1. User authentication. The network authenticates users to prevent illegal users from occupying network resources.

2. Network authentication. Users authenticate the network to prevent users from accessing illegal networks and being defrauded of key information.

This two-way authentication mechanism is AKA (Authentication and Key Agreement) authentication.

In addition to AKA authentication, other authentication methods can also be used. Before IMS AKA authentication is widely implemented, or under specific conditions (such as access to IMS through a fixed network ADSL connection), other authentication methods such as HTTP digest authentication can be used.

3G UMTS (Universal Mobile Telecommunication System, Universal Mobile Communication System), EPS (Evolved Packet System, Evolved Packet System), and IMS (IP Multimedia Subsystem, IP Multimedia Subsystem) networks all use AKA two-way Authentication mechanism.

On the 2G network, there is only user authentication and no network authentication.