Hong Kong's pro-democracy protesters are turning to mesh networks in order to avoid government censorship.
Download figures suggest demonstrators have begun using FireChat, a free app that enables users to send messages without a mobile phone signal.
The app was downloaded more than 100,000 in Hong Kong on Sunday alone, allowing activist to share news and messages of support. Earlier this week, it was revealed that the Chinese government had blocked Instagram on the mainland in an attempt to stop the spread of information from the protest area.
FireChat uses a technique known as "mesh networking" that enables data to travel directly from one device to another using Bluetooth or Wi-Fi. Although these are short range connections, as more people join the network grows and messages can travel further.
Mesh networks have previously proven useful for those caught in natural disasters and were used earlier this year by protesters in Taiwan and Iraq.
However, Hans-Christoph Steiner at the Guardian Project, which helps activists avoid censorship, warned that FireChat's lack of encryption could put demonstrators at risk.
"This is not nearly as bad as one central authority being able to read all the messages. Nevertheless, it is something that at-risk users need to be aware of," he said
While FireChat does aim to add encryption to the service in the future, protesters could currently be singled out by authorities as each Bluetooth communication is accompanied by an identifier called a MAC address.
While the authorities could ultimately block the use of FireChat with radio jamming technology, so far the software is proving an effective way for protesters to spread their message.