The government gives you a score, and the score is a measure of how trustworthy you are as a citizen.

And determines what you are allowed to do, like ever.

Boarding a train, getting a mortgage, all goes back to this score.

It's called social credit, it sounds like that show 'Black Mirror', but it's actually happening in China.

So how does that change you? Does it change you?

What does your life look like when your every move is watched?

The system's eyes are in Big Data artificial intelligence, and roughly 200 millions surveillance cameras.

And that's totally fine with Ou Yang Hao-Yiu.

She's 21, graduated from a good school with solid grades.

She's diligent, she is nice.

No surprise, she is a 752.

That's her rating with a private company working with the government on the algorithms with the social credit system.

The scores go from 350 to 950 and are based on habits and behavior.

Buy clothes or diapers, it's good; a lot of alcohol, too many video games, not so good.

Hao-Yiu's 752, put her a model citizen range and get her discounts and privileges, like using a share bike without a deposit.

She likes it, her friends do too.

They all have pretty high scores.

It's a mechanism like pushes you to become a better citizen, to build on a trust, especially on the Chinese market.

You are not going to be punished if you haven't done anything wrong.

I think that's the point, I think the system working as a warning or an alert to push people to be a good person.

And it's mandatory, when it goes national, social credit scores will be assigned to everyone of China's citizens for life.

And what's weird, it's that so many people seem okay with it.

It's complicated but China went from extreme poverty to economic giant pretty quickly, credit history system didn't grow at the same pace.

So people would default on loans and get away with it.

Adding scandals around fake food, tainted baby milk, counterfeit goods and what you've got is a big problem with trust.

So in 2014, the communist party called for a system to allow the trustworthy to roam everywhere under heaven;

while making it hard for the discredited to take a single step.

The model is a place called Rencheng, it's in Shandong Province.

It's orderly, streets are spotless and cars slow down which is unheard of in China

Words like 'honesty' and 'credibility' appear on propaganda posters.

Display cases show pictures of Rencheng's most honored citizens.

You start with a thousand points, and you can print out your report anytime.

You lose points for things like jaywalking, littering, tossing cigarette butts or spreading rumors.

Cameras do a lot of the surveillance work but it's pretty analogue too.

Like posters that list the way you can gain or lost points.

And each night, local TV shows the surveillance highlights of the day.

And then there is Jiu Ai-Ni, she's an information collector, a paid enforcer who walks around and writes down deeds about her neighbors.

Like the man who carried the drunk person home, things like this are good deeds, she said.

But the farmer overheard swearing and being rude, yeah, bad deeds.

Her quota is 10 a month.

She likes the work, thinks the city is better for it

The thing about the social credit system is that there isn't one single system, not yet.

Different places have different rules.

What do you do if you have bad social credit?

Well for one, you talk about it on weibo which is like twitter.

There are forums for discredited people to vent and get advice.

In Chongqing, we hooked up with Huang Wei-Jun.

He had a business until he was sued by a client and Huang refused to pay 90 grand to settle it.

So the court put him on a social credit blacklist, and things got way worse.

He explains that being blacklisted means he can't buy airplane or train tickets.

When he tries, a message pops up saying he's discredited.

By the end of last year, blacklisted people were blocked from booking 22 million flights and 5 million high-speed train trips, and the list goes on.

Being discredited makes it hard to get a job, a loan, a hotel room or put kids in certain schools.

Then, there's the public shaming, photo galleries of blacklisted citizens;

there's even an app that shows who around you is in debt.

In China, being monitored is nothing new but algorithmic surveillance makes it possible to collect data to build detailed profiles of people.

Especially the ones not loyal to the government.

Of all the videos surveillance cameras on the planet right now, nearly half of them are in China.

Are people bothered by privacy concerns?

So we think a lot of cameras keep the safety, it's really good.

They're good things, and lots of people, we can accept it.

And cameras are getting smarter, so the information that comes out for my image, identifies that I'm female, middle-age, talks about whether wearing glasses, shape of my face.

AI is taking them next level, they can do more than just see, they actually understand who they are seeing.

So at what point can the technology go too much? Does it already?

People don't care about it, but if the technology alerts too much, for example cross the red line, that's not very good.

How far off are we from needing to draw those red lines?

It's very hard to say, I think maybe in that case, maybe 10 years or 20 years, 15 years maybe.

That's not very long, it's coming.

It's coming. It's coming.

Where does it all go?

HaoYiu isn't so bothered, her score is high, life is good and she's used to living most of it online.

Soon, her education and medical records and any run-ins with the law will factor into her social credit score.

And wherever she goes, someone will follow and ask 'Who can you trust?'