The Chinese government has required that personal computer makers bundle a software that filters Internet content from July 1, according to a Ministry of Industry and Information Technology document seen by Reuters.

The free Green Dam-Youth Escort software, developed by Jinhui Computer System Engineering Co, can effectively filter unhealthy words and images, the document said.

The requirement is in order to consolidate the achievements of the online campaign against pornography, combine punishment and prevention, protect the healthy growth of young people, and promote the Internet's healthy and orderly development, it said.

China already has a system to block websites deemed objectionable. Internet police monitor sites, blogs and other online venues for pornographic or politically sensitive content.

Summer vacation is coming up, and many Chinese parents worry about what their children will see on the Internet. That's the purpose of the software, Jinhui founder Bryan Zhang said.

Even if you wanted to use it for, say, political content, you couldn't, because it's image distinction software that tracks pornographic images, Zhang told Reuters.

PC makers must report the number of computer units sold and software packages installed to the ministry on a monthly basis in 2009, and yearly starting in February 2010, the circular says.

Using the software is not compulsory. You can shut it down or take it out if you want to. With a password, you can turn it off at any time, Zhang said.

It's an optional tool to prevent access to pornography, just like anti-pornography software in the United States.

The Wall Street Journal first reported the news on Monday.

CONCERN

Homegrown brands like Lenovo and Founder dominate China's market, though global names such as HP, Dell and Acer have significant market share.

It is one of the world's fastest-growing PC markets, with research firm Gartner forecasting total PC shipments will climb by about 3 percent this year to more than 42 million units.

Acer said it was not aware of the new requirement, while rival Taiwanese maker Asustek said it was but had not yet been officially informed by the Chinese government.

Along with the rest of the industry ... we are studying it and working with relevant government and other parties to seek clarifications, said Dell spokeswoman Faith Brewitt.

Jinhui last year won a tender to supply filtering software to the ministry, according to government procurement information. The software was developed with the help of Beijing Dazheng Human Language Technology Academy Co.

Since then, the ministry has subsidized the company to make the software available for free downloads, said Zhang. It previously sold for 368 yuan ($54) a package.

The software will remain free for a year, and after that consumers will have to pay to continue using it, Zhang said.

It has already been bundled in over 50 million locally made PCs offered rural dwellers as part of China's economic stimulus package, according to a promotional website (www.lssw365.net).

It said the software is being used by 2,279 schools across China and had been downloaded 3.27 million times by end-March.

The U.S. embassy in Beijing said it was concerned.

We would view any attempt to restrict the free flow of information with great concern and as incompatible with China's aspirations to build a modern, information-based economy and society, an embassy spokesman said.

The software has a black list of sites with pornographic or violent content it blocks, said a customer service representative affiliated with a website offering the software for downloading.

The software also has a white list of permitted websites. Users can add or delete websites from the white list.

The software can be un-installed, the representative said.

Savvy Internet users can access sites outside China through virtual private networks or proxy servers. Netizens in China repost content or use oblique language to stay ahead of censors.

Pornography is easily accessed on the Chinese Internet.

(Additional reporting by Chris Buckley and Beijing newsroom)

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