China is striving for global leadership, and has the economic clout to realize its vision.

Apple yesterday removed Boom the Encryption Keyboard, an app that allowed Chinese internet users to bypass censorship, from the China app store, according to its developer.

Wang Huiyu, a New York-based Chinese citizen in his 20s, told Quartz that he developed Boom together with one of his university classmates during the outbreak of the coronavirus. Part of the motivation for Wang to develop the app, which went live on Feb. 15, was to offer people a chance to counter rigid online surveillance, and to provide them with an entertaining private messaging app.

According to an email sent by Apple to Wang, the app was removed because it contained “content that is illegal in China.” The app is still available in other regions, including Hong Kong, he said.

“I designed the app because I wanted to remind people of the importance of privacy, and my target customers are people born after 1995 or 2000. I feel those under 20 will be able to accept new things and ideas the fastest,” said Wang.

Boom encrypts text, both in Chinese and English, by turning them into emoji or Japanese or Korean characters, as well as rearranging lines of text in random order. The receivers of such messages can decrypt them by copying the emoji or characters using the app, with the original text then displayed automatically on the keyboard’s interface. As China’s blanket online censorship relies heavily on the detection of key words or even pictures containing sensitive words, apps like Boom can help users avoid such scrutiny.

Another app developed by Wang, which offered animated wallpapers featuring political figures including former Chinese leader Jiang Zemin, was also removed (link in Chinese) from Apple’s mainland China app store on the same day as Boom, he said.

Apple has removed apps from its China app store in the past for containing ”illegal content.” Among the apps that have been pulled were Quartz’s news app, which was removed from the China app store last year.

Apple did not immediately reply to a request for comment.

While most apps that enable encrypted messages and communications have long been banned in China, Wang said he suspects Boom drew the attention of authorities because of the way Chinese internet users quickly moved to preserve a particular coronavirus-linked article from being scrubbed by censors recently.

The article in question is an interview with Ai Fen, a Wuhan doctor who said she was reprimanded for alerting other people about the novel coronavirus. The article, published on March 10 by China’s Ren Wu magazine, was deleted within hours of its publication. Various versions of the article, including those reproduced in emoji, English, and even Hebrew, emerged after the deletion as people scrambled to save Ai’s story, part of a broader wave of efforts by internet users in China to prevent censors from removing crucial stories and memories related to the epidemic. Wang said downloads of Boom from mainland China surged after the incident.

Apple has been repeatedly accused of bowing to China by removing apps, such as a Hong Kong live map app that allowed protesters to crowdsource police movements during last year’s protests in the city.