Researchers at Citizen Lab have noticed a censorship crackdown on WeChat and Weibo in wake of the death of Nobel Peace Prize winner and human rights campaigner Liu Xiaobo last week.
The research group within the University of Toronto used a set of phones registered to WeChat with mainland Chinese phone numbers, and another set registered with numbers outside China.
By sending a number of messages to test which words were blocked, Citizen Lab concluded censorship from Beijing was "more expansive and blunt".
"Before his death, messages were blocked that contained his name in combination with other words, for example those related to his medical treatment or requests to receive care abroad," it said. "However, after his death, we found that simply including his name was enough to trigger blocking of messages, in English and both simplified and traditional Chinese."
"In other words, WeChat issued a blanket ban on his name after his death, greatly expanding the scope of censorship."
Citizen Lab also found Tencent-owned WeChat was blocking images referencing Liu Xiaobo throughout its services, and for the first time censoring messages between users.
The group's results showed 74 images were blocked on WeChat Moments, 26 blocked within group chats, and 19 blocked in direct messaging between users.
"It is unclear why only a subset of the images blocked on group chat were also blocked on one-to-one chat," Citizen Lab wrote. "It would be technically convenient to enforce censorship of the same sets of images in chat functions."
"One possible explanation is that censorship in smaller, more private spaces is most disruptive and noticeable to users as opposed to ones with larger audiences."
In all instances of censorship occurring on WeChat, the user is not informed that content is removed, Citizen Lab said.
The Chinese equivalent of Twitter, Weibo was found by Citizen Lab to be even more heavily censored.
Meanwhile, AP is reporting WhatsApp is partially blocked in China, with users unable to send images or voice messages via the service.
One service already banned in China, Telegram, had the prospect of a ban in Indonesia floated last week by Jakarta.
Telegram had too much content promoting radicalism, extremism and "hatred belief", and needed to be blocked to safeguard the "integrity" of the republic, Indonesia's communication ministry announced on Friday.
The web version of the messaging service can no longer be accessed in the archipelago, with preparations to also shut down the application if the company does not prepare standard operating procedures, the government said.
Telegram's CEO Pavel Durov said on Sunday the ministry had contacted them with a list of public channels with terrorism-related content but his team was "unable to quickly process" them.
Those channels are now blocked and it is forming "a dedicated team of moderators with knowledge of the Indonesian language and culture to be able to process reports of terrorist-related content more quickly and accurately".
Telegram, he added, had "several million" users in Indonesia.
As for the western world, Australia has made the running for the Five Eyes nations -- the United States, United Kingdom, Canada, Australia, and New Zealand -- on the topic of encryption and the problems it poses for law enforcement in recent weeks.
Last week, Australian Attorney-General George Brandis said draft legislation was being written to compel technology companies to turn over the content of end-to-end encrypted messages by the end of the year.
"Last Wednesday, I met with the chief cryptographer at GCHQ ... and he assured me this was feasible," Brandis said.
"What the government is proposing to do is to impose upon the companies an obligation conditioned by reasonableness and proportionality."
Brandis stated he believes the process of breaking into end-to-end encrypted messages can be done in almost real time, since GCHQ has told him it is possible.