HAMBURG – Somewhere on the far side of hacking, exploits become art.

Take the Newstweek system, an innocuous-looking wall plug that hijacks local Wi-Fi signals and feeds false news articles to people visiting websites such as the BBC or Le Monde. Plugged surreptitiously into the wall in cafes in Paris, London and elsewhere, and controlled by artists in Berlin, the system has sparked considerable confusion among unwitting web surfers.

Or there's the Transparency Grenade, which – when its pin is pulled – extracts images and web-site pages from local Wi-Fi signals, and funnels them to a screen that displays exactly what local phones and computers are looking at.

"I'm interested in producing a healthy, productive paranoia," said Julian Oliver, a Berlin-based artist that worked on both projects, presenting his work here at the 30th annual Chaos Communication Congress. "It introduces what I would describe as a healthy, healing process of change."

Indeed, in between serious discussions on the evolution of encryption theory or the dangers of NSA surveillance, the members of the Chaos Computer Club and its conference attendees are dedicated to demonstrating the artistic capabilities of hacking.

As befits a group concerned with tearing apart and recreating technologies, a number of these projects have to do with examining and subverting secrets, or exposing functions intended by their creators to be invisible. In many cases, the art is intended to make viewers question their relationship to technology or institutions of power.

Oliver is a founding member of a group dedicated to "critical engineering," which he defined as using engineering rather than art or design techniques to pose creative and critical questions.

Another of their projects, called the Packetbrücke (Packet Bridge, in English), involved hijacking the beacon frames, a kind of Wi-Fi network signal, that help phones determine their location without GPS. Signals from one location in a city were collected by an array of Wi-Fi receivers, then tunneled online to another location and rebroadcast, essentially fooling nearby phones into displaying erroneous locations.

"We have a running problem of an inability to see the inner workings of our technological environment," Oliver said. "We like seamlessness. I like to get to seamfullness, bringing the edges into view."

Trevor Paglen, another artist presenting at the conference, takes an approach to photography that is perhaps more familiar from the field of investigative journalism. He has spent years seeking to photograph evidence of government secrets – CIA rendition camps in Afghanistan, classified drones, spy satellites in space – and has had remarkable success (much of it previously documented here in Wired).

"Secrecy is a self-contradictory thing," Paglen said. "It's not efficient. If it has to be made out of the same stuff as regular stuff, it has to reflect light. It's visible. If you have secret airplanes, you can't build them in an invisible factory with ghost workers."

His work, which has been shown around the world, has produced remarkable results. Working with human rights activists and journalists, he and associates exposed front companies working with the CIA to fly prisoners to secret jails around the world, and located and photographed some of those facilities.

He discovered that secret groups within the military intelligence community often created uniform patches, and was able to collect a broad collection of these. One, for a classified military spy-satellite program, even turned out to depict an accurate satellite orbital path on the patch itself, enabling its purpose to be deduced.

"These are civic institutions," Paglen said, explaining his motivations. "I don't think that these guys who make patches, I don't think they get to win. I don't think we're going to do very well if we participate in the culture of fear we have toward own civic institutions."