An anonymous reader writes "A pair of researchers at Karlstad University have been able to establish how the Great Firewall of China sets about blocking unpublished Tor bridges.
The GFC inspects web traffic looking for potential bridges and then attempts "to speak Tor" to the hosts. If they reply, they're deemed to Tor bridges and blocked.
While this looks like another example of the cat and mouse game between those wishing to surf the net anonymously and a government intent on curtailing online freedoms, the researchers suggest ways that the latest blocking techniques may be defeated."
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