Barry Fox

Bluetooth, USB and HDMI are all flawed brilliance – great ideas for making life easier, but designed by computer engineers to create the kind of obstacle course we expect from a Windows PC.

HDMI can blank out pictures for no good reason. PCs lose USB devices or never find them. I tried a USB adapter that lets a PC rip LPs from a turntable. One XP PC smoothly installs the necessary USB audio codec driver; another can’t.

To pair Bluetooth devices, you have to hope Windows doesn’t insist on installing the wrong driver for a PC dongle, then learn about Discovery modes, recognise the device from a list of everything in the vicinity, enter the correct pass keys (which may be 0000, 1234 or whatever) and hope the pairing survives after the devices have gone out of range or been switched off.

The Eleksen roll-up keyboard for a smartphone is a treat, but only after you have jumped through Bluetooth setup hoops.

SIG, the Bluetooth Special Interest Group, was formed without the obvious simple design brief; bring two Bluetooth devices close together and press a button on each to approve pairing.

It has taken 10 years for the latest Bluetooth standard – version 2.1 + EDR (Enhanced Data Rate) – to make pairing easier by letting a device such as a headset go automatically into pairing mode for a short time when switched on. Version 2.1 can also use Near Field Communication (NFC).

A device such as a digital picture frame has an NFC passive transponder built in. When a camera with active NFC transmitter is brought very close to the frame, it invites the owner to press a key to authorise pairing. Then, with no need for a pass key, the devices communicate by Bluetooth.

SIG is promoting this, but is keeping quiet about recent joint research by BT’s Labs at Martlesham and University College in London on mobile wireless viruses.

The first wireless virus was found in 2003. Within three years, there were 800. Now there are many more. Some spread directly from device to device, so devices can become infected without going on the internet.

Infection is through ad-hoc and multi-hop networks. These are used to extend wireless internet access, let wireless sensors share data and help disaster relief. If one device is infected by malware, it can infect others in the network. The process is analogous to airborne disease infection.

Wifi uses Medium Access Control (MAC), meaning that devices listen before transmitting. If one device detects that another is already transmitting on the same frequency, it waits for a random time before trying again.

So every device in the vicinity gets a random place in the same queue. This has the happy side-effect of ‘throttling’ virus infection. But Bluetooth does not use MAC; devices rapidly switch frequency to avoid clashes.

Until recently, most devices were Class 2, with only 2.5mW of power and a 10m range, so there is less risk of infection. But the newer Class 1 devices, with 100mW, reach 100m.

I asked Michael Foley, executive director of SIG, about the research findings. “Most of these viruses work in the same way,” he said. “First they ask the user to accept a data transfer. Then they ask permission to install. People should not accept and install from sources they don’t recognise.

But often the virus is clever. It keeps asking the same question. Every time the user says ‘No’ it asks again. So the user may eventually hit ‘Yes’ just to get rid of the questions. On the Bluetooth website, we try to advise people to get out of range if they get persistent questions.”

I looked but found no obvious sign of advice on the SIG site. SIG is playing the government game of burying bad news, where it will only be found by someone who knows what to look for and where to look.

Of the warning notices I eventually found, one assured that “Bluetooth wireless technology is fundamentally secure”; the other told how “Bluetooth SIG is constantly at work to keep the technology secure”. This isn’t what the BT/UC report says.

This article appeared in the Winter issue of PCW

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