The ones on the outside are basically there to form a human wall to protect the identities of the people that are actually up at the post breaking open this camera, getting into the guts and ripping them out.

We use umbrellas.

We also use spray paint to blind the cameras.

If the cameras are way up high, we will try to use lasers.

Protesters in Hong Kong fear they are being watched and tracked when on the streets and just showing up may expose them to retaliation from the government.

More than a thousand people have been arrested since the pro-democracy protests against China's growing control over Hong Kong started in June.

You might be doing something that you think is perfectly fine right now but then later you might be charged based on camera footage, based on geolocation data from your mobile phone and so on.

Lokman Tsui researches personal data protection and digital security in Hong Kong.

He supports the pro-democracy movement.

We don't know what kind of data the Hong Kong law enforcement is sharing with the Chinese law enforcement.

While covering pro-democracy demonstrations in Hong Kong we found that protesters have developed a number of tactics to protect their identities and avoid detection both online and on the streets.

Before the streets become chaotic, the scene is usually pretty calm.

Some are already decked out in protective gear and busy on their phones to exchange files with somebody nearby.

Those with iPhones use AirDrop.

Sending pictures through AirDrop is anonymous.

People don't know who is sending them, and you don't know who is receiving them.

Desmond Fung has joined protests almost every weekend since June.

He says the central nervous system of this leaderless, protest movement is the anonymous, encrypted messaging service, Telegram.

Downloads of the app in Hong Kong have soared since the protests began.

What are we seeing here?

If some citizens spot a lot of police cars in a specific location, they will notify the group.

So people at the frontline can be safer.

Aren't the police in there as well reading everything that you write?

We have a term caller "capturing the ghost."

It means we will try to discover who are the police and kick them out of the groups.

Desmond said there are ways to sniff out spies but he didn't want to share specifics or show us the private chats on his phone because sometimes these chats are about taking radical measures.

These are the most hard-core protesters.

Police consider them violent and often target them for arrest.

They're getting ready to go up to the front and actually confront the police.

They're the ones with the most at stake in terms of obscuring their identity.

Protesters aren't just worried about surveillance cameras but also the police's own camera crews.

Protesters worry any footage could later be used as evidence against them.

The police will try to find you if you don't cover all you face.

Even your ears will be evidence to arrest you.

Many protesters' kits also include this.

Laser pointers have become a thing in these protests.

They're used to distract the police and blind cameras.

Protesters can buy these kinds of laser pointers at any electronic store and they typically cost about $10.

Police have called them offensive weapons which means they can arrest someone for causing injuries with lasers.

Our colleagues were injured by these items, and our video-camera sensors were damaged.

Police also cite medical experts who say the beams can cause permanent eye damage.

It is by no means an offensive weapon.

I would not be worried about pointing it at myself because there is no problem at all.

Protesters' methods can also be very DIY.

He's handing out tinfoil and what he's doing is he's wrapping people's Hong Kong IDs with tinfoil in hopes that a law enforcement official won't be able to scan the ID remotely.

Protesters want to prevent police from tracking them via the radio frequency identification chips embedded in their Hong Kong identification cards, subway cards or credit cards.

The government says only authorized sensors that are within two centimeters of the smart IDs are able to pick up the information.

To avoid having their movements recorded on their regular subway cards they pay for one-way tickets home from the protests with cash.

Using a single-journey ticket will make it harder for the police to trace it back to us.

These tactics to avoid surveillance go hand in hand with avoiding arrest.

But if it does happen protesters also use a simple hack to try to protect the data on their phones.

We do not use our fingerprints to unlock our phones.

We are quite afraid if we were arrested, the police could use our fingerprints to gain access.

We also won't use face detection on our phones.

Here in Hong Kong you have the right to not reveal any knowledge that might incriminate you.

So a pin code is knowledge but your fingerprint or your face is not necessarily knowledge that you reveal to the authorities.

As the movement evolves police are deploying new tactics to tag protesters, like using water cannons laced with blue dye.

Hanging over all of this is the fear that their identities will get swept up digitally and end up in a database, perhaps in Beijing that tracks them and follows them for the rest of their lives.

Protesters told us they'll keep playing the cat and mouse game of avoiding surveillance while defying the government.

They say they won't stop until their demands are met, including an inquiry into police brutality and direct elections.

The Hong Kong government has taken some action like withdrawing a controversial extradition bill that sparked the protests.

It says it is looking for ways to start a dialogue to address the discontent.

In the end the odds are stacked against them.

It's essentially a group of young Hong Kongers with laser pointers and umbrellas against the will of Mainland China.

How do you see this playing out for the future?

I don't know, actually.

The chance of success is, it's almost zero, but we still need to do this because of the justice, because we love this place.