Google is encrypting search worldwide. That’s bad for the NSA and China’s censors.

China’s Great Firewall, as the world’s most sophisticated Internet censorship system is known, is facing a new challenge as Google begins to automatically encrypt searches there as part of its global expansion of privacy technology.

Google and other technology companies responded to documents leaked by former National Security Agency contractor Edward Snowden with major new investments in encryption worldwide, complicating relations between the companies and governments long accustomed to having the ability to quietly monitor the Web. Googling the words “Dalai Lama” or “Tiananmen Square” from China long has produced the computer equivalent of a blank stare, as that nation’s government has blocked Web sites that it deemed politically sensitive.

But censors spying on Google’s search queries in China increasingly are seeing only gibberish, undermining the government’s ability to screen them. China -- and other nations, such as Saudi Arabia and Vietnam, that censor the Internet on a national level -- will still have the option of blocking Google search services altogether. But routine, granular filtering of content will become more difficult, experts say. It also will become more difficult for authorities to monitor search queries for signs that an individual Internet user may be a government opponent, experts say.