Network designed to short-circuit digital spies.

Byline: Carlotta Gall and James Glanz

SAYADA, Tunisia -- This Mediterranean fishing town, with its low, whitewashed buildings and sleepy port, is an unlikely spot for an experiment in rewiring the global Internet. But residents here have a surprising level of digital savvy and sharp memories of how the Internet can be misused.

A group of academics and computer enthusiasts who took part in the 2011 uprising in Tunisia that overthrew a government deeply invested in digital surveillance have helped their town become a test case for an alternative: a physically separate, local network made up of cleverly programmed antennas scattered about on rooftops.

The State Department provided $2.8 million to a team of U.S. hackers, community activists and software geeks to develop the system, called a mesh network, as a way for dissidents abroad to communicate more freely and securely than they can on the open Internet. One target that is sure to start debate is Cuba; the U.S. Agency for International Development has pledged $4.3 million to create mesh networks there.

Even before the network in Sayada went live in December, pilot projects financed in part by the State Department proved that the mesh could serve residents in poor neighborhoods in Detroit and function as a digital lifeline in part of Brooklyn during Hurricane Sandy.

But just like their overseas counterparts, Americans increasingly cite fears of government snooping in explaining the appeal of mesh networks.

"There's so much invasion of privacy on the Internet,'' said Michael Holbrook, of Detroit, referring to surveillance by the National Security Administration.

"The NSA is all over it,'' he added. "Anything that can help to mitigate that policy, I'm all for it.''

Since this mesh project began three years ago, its original aim -- foiling government spies -- has become an awkward subject for U.S. government officials who backed the project and some of the technical experts carrying it out. That is because the NSA, as described in secret documents leaked by the former contractor Edward J. Snowden, has been shown to be a global Internet spy with few, if any, peers.

"Exactly at the time that the NSA was developing the technology that Snowden has disclosed, the State Department was funding some of the most powerful digital tools to protect freedom of expression around the world,'' said Ben Scott, a former State Department official who supported the financing and is now at a Berlin policy...