CtOS

Produced by the Blume Corporation,  CT OS, or Central Operating System, controls Chicago. The system is the fundamental weakness of the city, as it can be hacked into through the use of a chain of backdoor viruses and used as a weapon against the city and its inhabitants. The CT OS also stores information on each inhabitant of the city in control centers and gathers new information with the help of surveillance. Various control centers (data servers) are dotted around Chicago, which can be taken control of, along with CT OS towers, allowing Aiden to access the information it stores and the mechanisms it controls. Various communication sites are placed between the centers, allowing for quick transfer of data over large distances. Though CT OS has reduced and is still reducing the overall crime levels of Chicago, that doesn't mean that the city i s as protected as Blume says it is. CT OS is tied to a satellite which acts as a safety valve which can shut down the entire system if necessary.

Controversy
One question that is frequently asked about the CT OS is: Who controls the system that controls Chicago? One negative that has been noted about the CT OS is that large businesses could use the data stored by  CT OS to maximize profits. It has also been noted that control of the system could fall into the wrong hands, like those of hackers such as Aiden Pearce, Damien Brenks, and Defalt.

The fact that control of CT OS could fall into the wrong hands has clearly been brought to the public's attention by a hacking collective known as DedSec. The collective hacks into the system and misappropriates its abilities to use it for its own purposes, such as invasions of privacy or data collection, simultaneously emphasizing CT OS's great power and security flaws.

Systems controlled by the CT OS

 * Blockers and Road Spikes
 * Bridge Access
 * Electric Grid
 * Lights / Traffic Lights
 * The L Train
 * Underground and above-ground steam pipes
 * Crime Prediction System
 * Security Cameras
 * ATMs / Bank Accounts
 * TVs and Video Adverts
 * Citizens' Private Information
 * Cellular communications
 * Internet-connected devices
 * Facial Recognition
 * Power Transformers
 * Light Houses

ctOS 2.0
ctOS was upgraded to 2.0 at the end of Watch Dogs. This led to the events of Watch Dogs 2. After ctOS was completely crippled, Blume moved their chief development to Silicon Valley for further development. Tying into the power of the "Internet of Things", ctOS 2.0 quadrupled in power. Following revelations from Aiden Pearce through DedSec, activists and hackers have started to resist Blume and their ctOS scheme.

Trivia

 * CT OS was upgraded to CT OS 2.0 with assumed upgraded security features after Aiden Pearce rebooted it.
 * CT OS was also said to be introduced to other cities.
 * The upgrade may also lead to a sequel game.
 * The ctOS is mentioned in an Easter Egg in Assassin's Creed IV: Black Flag.