Here is what I think I would do.
Since you cannot communicate with others openly, you have to do it indirectly by "sending a message".
This is a solo mission, and you are going to be on your own most likely.
The only way to defeat that type of system is by sabotaging it from the inside.
Join the security forces, work your way into the system.
Then start breaking things, secretly or make it look "accidental".
Let innocent people escape and backstab your fellow officers.
I know it sounds very dirty and low down, but hey so is a police state where they control your life.
Just become one of "them" and wreak havoc from the inside. Sabotage, misinform them, murder, anything goes as there is no "Law" in a 1984 society
there is only brute force and submission.
When the people see you fighting the good fight, and see the mess you leave behind, they will copy you. They will see the point in it, and want to
emulate that behavior. It is only natural.
We do have 1 dillemma I can think of right away. If in that future world, they turn all policemen into hybrid - cyborg type machine people. Well,
don't become a cop than because we want to AVOID becoming a Cyborg.
In the case of Cyborgs and other disgusting freakshows, our only choice left is to simply gather weapons and fight an all out war with them until they
kill us.
Get in some cheap shots though and try to evade detection.
Examples : Disable all of their cameras and possibly try to jam their communications channels. Set booby traps, etc.
Fight a guerrilla war. You have to.