Chatter Protocol Authority
From Halopedia, the Halo wiki
The Chatter Protocol Authority or CPA polices the "ChatterNet", a communication network that connects Chatters all over Earth together for communication, file sharing, and other tasks performed by the general population [1].
Hacking the ChatterNet, while illegal, is a common practice, and one which colonials may depend on in order to evade immigrations officials through use of false identities [2].
