In Brave New World (1980), we cannot see any scene related to security like hacking, encryption, passwords, or cyberattacks. However, we can guess that network security is important to maintain this society. Systems like the Hatchery and Conditioning Centre and hypnopaedia are controlled with electronic equipment. If these systems were hacked, people's abilities cannot be controlled, and children could be taught values that conflict with the society. As a result, the society will collapse fundamentally.
The likelihood of these systems being hacked is incredibly low, though, as the vast majority of the civilians believe everything they see and are happy with where they are in life. There is no money in this world, so the only reason one would have to hack these systems is a need for information or in retaliation against the society. Again, almost no one harbors these feelings, and those who do likely do not have the knowled ge or means to commit such acts.