How do mobile communications get sent from one cell phone to another without being intercepted and read?

Question

One c

In: Engineering

Answer 1

Starting from 4G, UEA and UIA features of a cell network all became mandatory, in 2G and 3G they are partially or completely optional.

UIA doesn’t encrypt user data, it only encrypts the commands and integrity protection frames, so the data is plaintext but only the authenticated parties can generate and verify them, so the communication cannot be forged.

UEA encrypts the actual user data frames so nothing apart from the cell towers and user equipment that has the user’s USIM cards can encrypt and decrypt them, making the content of the communication private.