A Chinese encryption expert has been sentenced to death for selling 150,000 classified documents to unnamed foreign intelligence agencies, according to an item broadcast on China's state television. South China Morning Post (SCMP) reported that Huang Yu, 41, handed over "90 'top confidential', 292 'confidential' and 1,674 'secret' files which leaked cipher codes for Communist Party, government, military and financial communications."

Huang obtained these while he was working at a research institute in Sichuan province, which develops China's cryptographic communication technologies. Huang joined the institute in 1997, and started selling classified information in 2002 when he was told that he was going to be dismissed for his poor work.

According to an article on China Daily, he contacted a foreign intelligence agency online to sell confidential documents he had accessed at the institute, and met up with a foreign spy at a hotel in a Southeast Asian country in June 2002. "During the meeting, Huang gave three electronic documents containing military secrets to the foreign spy for which he was paid $10,000 and was promised a monthly sum of $5,000 for more documents."

After that, Huang traveled abroad regularly to Southeast Asia, Hong Kong and Macau, under the guise of attending meetings, but in fact to hand over more documents held on laptops and data storage devices.

According to SCMP, when Huang was laid off in 2004, he continued to gather and sell top-secret information obtained through his wife, other relatives, and former colleagues. In total, Huang is said to have earned around $700,000 (£500,000) in 21 deals over 10 years. He was caught in 2011, in part because of his sudden and unexplained wealth and frequent trips abroad.

As well as imposing the death sentence, the Chinese authorities also confiscated Huang's earnings. His wife was jailed for five years, his brother-in-law for three years, and 29 of Huang's former colleagues were punished. The Chinese state television report did not indicate whether the death sentence had been carried out or not.

As a story by Reuters published in The Guardian notes, the state news provided "unusual details of a kind of case rarely mentioned in public." Presumably the news of Huang's spying and the death sentence he received for it was meant as a warning for anyone tempted to supplement their income by following in his footsteps—or to become another Snowden by blowing the whistle on China's global spying activities.