An ostensibly priggish Chinese government has mandated that all PCs sold in the country ship with a special piece of anti-pornography censorship software starting July1.

Well, at least that’s the way it’s being positioned anyway.

It’s being received as hard-core government control over what the Chinese access over the Internet.

The filtering software was developed under a $3 million contract by Jinhui Computer System Engineering Company in concert with Beijing Dazheng Human Language Technology Company and is pointedly called “Green Dam-Youth Escort.”

The Wall Street Journal says the word green in Chinese is used to mean illicit-free and official Chinese go on about the purity of their young folk.

However, the software can be used to block sites based on keywords as well as URLs.

It will come with a database of constantly updated blocked sites – which ones the user will never know. Supposedly it doesn’t monitor or report back to a third party – at least not yet – and can supposedly be disabled with a password.

Jinhui founder Bryan Zhang told Reuters that it’s “image distinction software” and can’t be used to block political content. He also told Reuters its use wasn’t compulsory.

China has 250 million Internet users, according to the AP, more than anywhere else, and thanks to the so-called “Great Firewall” the government already blocks access to political blogs, sites and chat rooms at the ISP level, a system that can and is circumvented.

The Green Dam software, designed to work with Windows, will be free to OEMs but of course adds the cost of validating the stuff to ensure it doesn’t bugger other software, not to mention the OEM appearing like a heel.

Its use will be free for a year and then consumers will have to pay to continue to use it, Reuters was told.

The Journal says it can be installed on the hard drive or come on a compact disc.