Authorities in Beijing have revealed that a Chinese scientist who was convicted in 2015 of selling state secrets to foreign spy agencies was executed in 2016, one of several "shocking" spy cases.
The death sentence and execution were disclosed in a new documentary produced by the Ministry of State Security, China's top counter-espionage agency, which profiled 10 prominent spy cases from the past.
The documentary - Led by Innovation, National Security Sharpens the Sword - which was aired on Sunday by state broadcaster CCTV and has been posted to the ministry's social media page, is part of a campaign to mark the annual National Security Education Day.
The event, which is promoted by various local governments, including Hong Kong and Macau, is also intended to remind the public to remain vigilant about national security threats and report suspicious acts.
According to the documentary, Huang Yu, then a researcher at a top secret communication system development project, sent a note to "the website of a certain country's spy agency" containing classified Chinese military codes.
Huang was bitter after being removed from a unit that was working on the project due to poor work performance and had indicated he wanted to defect, the report said.
After the authenticity of the codes had been confirmed, Huang was recruited by the unnamed foreign spy agency and given training in Hong Kong and Bangkok. The documentary said he not only sold "core secrets" through his work, but also duped his wife - an employee at the same institution - into copying confidential material so he could pass it on in return for additional payments.
Huang was said to have leaked "a shocking amount" of confidential information about the communication systems used by the Communist Party, government agencies, the military and industries such as finance and telecoms. These included design, technical specifications, secret algorithms, source codes and programmes, the documentary said.
Huang was handed the maximum penalty for spying that caused "serious harm" to China's national security and was executed in May 2016.
The documentary also revealed new details about a former researcher from Taiwan who had been stealing secrets from mainland China while based in the Czech Republic.
Cheng Yu-chin, who was sentenced in 2022 to seven years in prison for espionage, "long had Taiwan independence ideas" and had been recruited by Taiwan's intelligence agency while studying for his PhD in Prague, the programme said.
Cheng had been paid NT$2.76 million (US$85,467) by the Taiwanese government to steal intelligence-related research reports and identify potential infiltration targets during multiple visits to the mainland, according to the documentary.
Cheng had previously worked as an assistant to Cho Jung-tai, the former secretary general of the Taiwan cabinet, who has been selected to be the island's next premier.
The documentary also profiled the case of Lee Henely Hu Xiang, a businessman from Belize who was sentenced in 2021 to 11 years in prison for helping to fund the Hong Kong protests, as well as the cases of the "two Michaels" - Canadians Michael Spavor and Michael Kovrig - who were detained in China in 2018, in apparent retaliation for the arrest in Vancouver of Meng Wanzhou.
Meng, the former chief financial officer of Chinese telecoms equipment giant Huawei Technologies had been detained in Canada on a US warrant, which the documentary said showed how China had fought the West's long-arm jurisdiction and efforts to undermine the country's political stability.
Quoting media reports that Spavor reached a C$7 million (US$5 million) settlement with the Canadian government in March this year, the documentary said Canada's "slander" in labelling their cases as "arbitrary detentions" had been "self-defeating".
The documentary concluded with what Chinese regulators have called a "rectification" of Shanghai-based consultancy firm Capvision Partners. The due-diligence company had been raided by authorities last year over national security risks in areas such as defence, technology, energy and resources, and medicine.
China said some of Capvision's clients had close relationships with foreign governments and military intelligence agencies.
"After foreign countries mastered this important and sensitive information, they implemented precise sanctions on a series of Chinese companies, causing significant harm to our country's industrial development and economic security," the programme said.
Chen Yixin, the state security minister, reiterated the ministry's priorities in an article published on Monday in the Communist Party's top theoretical journal Qiushi.
He said China's national security agencies will focus on major and outstanding risks, including "anti-subversion, anti-hegemony, anti-separatism, anti-terrorism, and anti-espionage struggles".
Also on Monday, a commentary in the Communist Party mouthpiece People's Daily said China has made breakthroughs in safeguarding national security in the past decade, making it a leading country "with the best sense of security".
"We have withstood and fought back against extreme external suppression and containment, and on a series of major issues involving Hong Kong, Taiwan, Xinjiang, Tibet, maritime affairs, and human rights, we have fought hard and won one tough battle after another," it said.