A counterpart and alternate Operative System exists within the CTOS servers, called the CTZNOS.
Very little is known about this operating system, except that it is somewhat "hidden" in the CTOS server rooms and created with a different purpose, possibly a private variant of the usual CTOS.
Aiden can hack a CTZNOS computer in order to get a video log stored from the computer. What it suggests is that the operating system is connected by every device that contains a camera, where it profiles the citizen's ID, their occupations, and their status. The videos only shows frames that models the citizen, as well as the environment and the analizing system that detects almost anything, though, in other videos, the system fails to check parameters or are simply interrupted. These videos will show strange situations of everyone, being profiled by the camera without being noticed (much like Aiden's Profiler). These videos only contains a few seconds of recording that will eventually stop and exit automatically.
These videos can be seen either from a CTOS Control Center or from The Bunker (an ex-CTOS facility, hence the computers). They can be viewed at these places and, in the case of the Control Center, once the player breaches the security systems and able to the server rooms (in the first time, before hacking the main console).
- One of the videos shows a bus driver with a prostitute. There's no buses on the actual game, suggesting the bus driver is from another location.
- Aiden access them through a special code (DED//SEC...), which leads to a logo of "The Randomizer", from DedSec. This implies that DedSec runs these video logs or they gather them from the CTZNOS, reinforcing the theory that the OS is "overwatching".
- CtznOS seems to be a play on the word citizens.