Both protesters and the authorities in Hong Kong are using complex combinations of technology, reports Devangshu Datta.
In mid-February, the city-state of Hong Kong exploded with a series of protests that continue.
Some of the demonstrations have drawn about two million people. That's an incredibly large number and a very high proportion of the city's 7.5 million citizens.
This has turned into a cat-and-mouse battle between protesters and the authorities, with both sides using complex combinations of technology.
The authorities use cutting-edge surveillance technologies, and data mining to anticipate the build-up of rallies. They use face recognition technology, data-mining and drones to identify individual participants. They use tear-gas and water cannons to break up rallies.
The protesters have adopted a decentralised, leaderless model in response.
Vast groups have been created on private messaging apps and dating platforms where rallies are referred to as 'picnics' and Pokemon Go meets.
Localised messaging apps have been used to coordinate protests when mobile services have been overwhelmed by traffic or deliberately shut down.
Laser pointers have been used to disable surveillance cameras. Face masks are used to thwart face-recognition systems.
Pictures of rallies with faces pixelated or blurred have been taken by drones and streamed out to prevent censorship, putting a lid on the troubles.
Tear gas grenades are deactivated by squads that douse these with water.
Hong Kong is an unusual place. It has a young, highly tech-savvy population. It has a per capita GDP of $ 48,000 which is almost six times as high as Mainland China and places it firmly in the global top 10 in terms of wealth.
It is also a free-trade zone with its own currency.
Four telecom service providers blanket the city with excellent mobile network. There are no dead zones in Hong Kong -- you will get a rock-solid, multi-bar 4G signal everywhere.
The city has many free, public Wi-Fi zones and many areas with networked surveillance cameras.
Hong Kong has insanely high mobile penetration. Around 85 per cent of residents have smartphones and the mobile penetration is over 250 per cent.
Most locals carry two or three dual-SIM devices, using one number to stay in touch with their families, one for work, one for friends and another for gaming, gambling, online banking and trading.
Due to its vibrant stock market and startup ecosystem, Hong Kong also has a large number of resident techies.
Hong Kong is also an anomaly due to its 'two-system' political status. The local laws are liberal with press freedom, no internet censorship or filtering, elections by secret ballot and guaranteed personal freedoms.
At the same time, HK is controlled by the People's Republic of China, or PRC, which constantly monitors everybody on the Mainland using repressive laws, sophisticated face-recognition systems and blocking popular social media platforms and apps that don't have servers within the PRC.
The PRC has developed what is known as the 'Great Firewall'. The State employs thousands to monitor content.
It has a social credit system in which citizens who have not paid their electricity bill, for instance, may be named and shamed by forcibly changing their 'hello tune' to urge callers to persuade them to pay up.
If social credit is poor, travel may be prevented. Leaked data from a hacked server recently indicated that face-recognition systems are routinely used to keep track of people, even characterising foreigners by name and race in Beijing's diplomatic enclave.
Under the 1997 agreement, when Britain returned HK to the PRC, the HK constitution continued to guarantee personal freedoms.
But in 2014, the PRC insisted on imposing an administrator -- a non-elected individual who is the equivalent of a governor. That led to a round of protests.
Some of the 2014 protesters have been arrested who have faced jail terms of up to seven years for 'causing public nuisance' and similar charges.
In February 2019, the Administrator, Carrie Lam, presented a bill that would allow HK-ites facing certain charges to be extradited to the Mainland for trial.
Many things that are not crimes in HK carry jail sentences in the PRC.
That bill has sparked the ongoing protests, which have clogged the streets and led to HK’s administrative centres being invaded and ransacked. Even though the bill has been indefinitely withdrawn, the protests continue.
Protest organisers have issued advisories and online manuals advising citizens on the best ways to participate in rallies, stay safe in real-time and avoid being recognised to prevent repercussions. They have also raised money online through crowd-sourcing methods.
Many of these efforts have involved using platforms designed for other purposes, as well as more traditional social media.
While Facebook and Instagram have both been used to spread messages, dating app Tinder and gaming platforms like Pokemon Go have also been deployed.
The messaging app, Telegram has one key advantage over the more popular WhatsApp. Telegram allows setting up huge groups -- the maximum number of people in a Telegram group is 200,000 -- whereas WhatsApp is limited to 256 per group.
Hence Telegram has become the messaging app of choice for HK protesters with many groups containing over 50,000 persons.
Those groups are administered by persons using throw-away, pay-as-you go SIM cards to avoid being identified.
Telegram doesn't have end-to-end encryption by default, but 'protest manuals' tell participants how to switch on that option.
Group members don't go to a rally. Instead, they enjoy a 'picnic', or attend 'meditation classes'.
Since February, the service has faced huge coordinated Distributed Denial of Service (DDoS) attacks, which, it says, come from an 'actor-State'.
Another messaging app, FireChat has also seen millions of downloads. FireChat was designed to allow friends to stay in touch locally in crowded events, such as music concerts.
Mobile networks get overwhelmed if thousands are using one cell at the same time. FireChat allows groups to connect using Bluetooth and other peer-to-peer technologies even when there is no mobile network.
FireChat has been used extensively in Iran, Iraq and Kashmir by protesters, but HK has seen its deployment raised to an art-form in the past six months.
The protest movement has put a lot of thought into enabling anonymity.
Remaining deliberately leaderless and faceless has prevented shutdown by selective arrests of organisers.
Protesters have been advised to stop using Chinese social media apps, such as Weibo and WeChat, which are susceptible to Mainland monitoring. The advisories offer instructions on how to delete such pre-installed apps from smartphones.
Protesters avoid using Octopus, the HK smartcard, commonly used to travel by metro. Octopus has unique serial numbers and can potentially be traced if a credit card has ever been used to recharge the card.
Hence there has been a spike in sales of single-use paper metro tickets.
While the economy has been affected by the disruptions, there has been a spike in the sales of lasers and face-masks.
Face masks can not only block face-recognition programs but also offer protection from teargas.
Lasers are pointed at cameras to prevent them from taking pictures and recording videos, which could then be used to either coordinate crowd-control in real-time or identify individuals later. Lasers can also burnout camera sensors.