Want Wi-Fi? Learn the secret code

Warchalking, as the practice has been coined by Matt Jones, entails simply drawing a chalk symbol on a wall or pavement to indicate the presence of a wireless networking node. If you see one of these symbols, you should--in theory at least--be able to whip out your notebook computer equipped with an 802.11 wireless networking card, and log on to the Net.

The idea of organized wireless hot spots, where people can log on at cafes, exhibition centers, airports and the like, is nothing new. BT Group has ambitious plans to create a commercial network of at least 400 high-speed wireless hot spots by next summer, and plans to have 20 up and running by August.

BT's vision, which entails providing access only to subscribers of its OpenZone service, required a change in the law to allow commercial use of the 2.4GHz part of the radio spectrum without a Wireless Telegraphy Act license.

But warchalking is remarkable because it is based on an ad hoc process of people discovering Wi-Fi nodes, whether commercial or not, and signaling their presence with chalk symbols. It is also remarkable for the reception the idea has had.

"I've been a bit overawed by everything, to be honest," said Jones, who came up with the idea after seeing students of the U.K. Architectural Association in what they called a "wireless Internet performance." The students had chalked an office plan on the pavement of London's Bedford Square, and sat out in the virtual office with laptop computers hooked up to the Internet over a Wi-Fi connection.

"I thought it seemed like a really nice idea," said Jones, who has an architectural background himself. "I have only had a wireless networking card for two months myself, and was interested in how it could change a city."

Several days later Jones was chatting with some friends, and someone mentioned the symbols that hobos used to use. "These were all about making visible what might otherwise go unnoticed," said Jones. After spending half an hour in Adobe Illustrator, Jones set up a Web log to publicize his idea, e-mailed the address to a few friends, and waited.

That was Sunday. By Tuesday, the popular Slashdot.org Web log in the United States had picked up on the story and the flood of e-mails began, including ideas to expand the basic set of three symbols to include the direction of the node.

The first attempt at drawing up symbols resulted in three simple designs: two semicircles back to back to indicate an open node; a circle to indicate a closed node; and a circle with a "W" inside it to indicate a WEP (Wireless Equivalent Privacy, a security protocol) node, which will probably be inaccessible to the public because such nodes use encryption for security. Each symbol has a Service Set Identifier (SSID) at the top, which acts as a password to the node. SSIDs are easily obtained using readily available sniffing software.

"The idea of the warchalking blog (Web log) was to put an imperfect idea out there and see what happened," said Jones. "It has been interesting to see how it has happened, but it has grown so fast it does not really feel like my idea anymore. I feel more like the gardener than the builder." Nevertheless, Jones hopes to finalize version one of the runes by the end of this week.

The idea of the warchalk symbols, said Jones, is that they should give just enough of a visual cue to indicate that it is worth firing up a notebook or PDA (personal digital assistant). Some suggestions have concentrated on touring the city with a notebook and GPS (Global Positioning System) to find wireless nodes, and then building an online database, but according to Jones this misses the point: "Using chalk runes breaks the cycle, because otherwise you would have to fire up your computer and log on anyway to find where the nodes are."

And the attraction of warchalking is its simplicity. Jones likens it to the apocryphal tale of how NASA spent 10 years and millions of dollars to make ballpoint pens work in space, only to send its astronauts up with pencils. There are other attractions of the chalk approach too.

"Some people have asked why not use stickers or paint," said Jones. "But the idea of chalk means that people have to go around and renew the symbols to the network is constantly revalidating itself and checking its own integrity. Also, using chalk won't piss too many people off." By using chalk, warchalkers should be able to avoid the fate of IBM, which was fined $100,000 for spray painting its "Peace, Love and Linux" ad campaign on the sidewalks of San Francisco last year.

There have been reports of system administrators expressing concern at the idea of having their wireless networks probed and exposed for all to see, but according to Jones there is a positive side to this. "If someone chalks the fact that you're exposed and you're a (system administrator), you can see it. You know you're exposed, and then you can decide what you want to do. I have already had e-mails from some (system administrators) who said they love the idea. Several even said they will print the symbols on a card and put it in their office windows."

However, the idea does not appear to be universally popular. The organizers of London-based community wireless project Consumer.net, for instance, do not appear to be overly impressed.

"I am one of those people trying to seriously encourage community networking, and if that activity is seen to be some sort of cracker plot it will be damaged," wrote one Consume.net member on the Slashdot Web log.

ZDNet U.K.'s Matt Loney reported from London.