Privacy group warns of web browser 'fingerprinting'

Most browsers have unique signatures that allow web site owners to see exactly who is visiting their web site, according to research by the US privacy organisation.

The EFF suggested that browser fingerprinting should be considered alongside cookies and IP addresses when discussing web privacy and the ability to track surfers.

The group also urged browser developers to reduce such privacy risks in future versions of their code.

The findings are the results of an EFF experiment using a site that anonymously logged the configuration and version information of volunteers' operating systems, browsers and browser plug-ins, and compared the information with a database of configurations collected from almost a million other visitors.

The EFF found that 84 per cent of the configuration combinations were unique and identifiable.

Browsers with Adobe Flash or Java plug-ins installed were even more likely to give unique configurations, while browsers less likely to do so were those that block JavaScript or are configured to limit the information shared with web sites.

"We took measures to keep participants in our experiment anonymous, but most sites don't do that," said EFF senior staff technologist Peter Eckersley.

"In fact, several companies are already selling products that claim to use browser fingerprinting to help web sites identify users and their online activities.

He added that the experiment is "an important reality check" which proves how powerful these tracking mechanisms are.