Security experts have long warned internet users that they could be held responsible for the criminal use of networks which have been left open for third party use. BT says that it has put security in place to ensure that users of shared networks are identified.
BT has signed a deal with Spanish shared-wireless specialist Fon. Fon sells wireless routers which share broadband capacity with other Fon users.
BT's system will carve off a section of a user's broadband connection and share just that part with third parties. It will only share it with other BT users who log on to the shared portion of the network.
A BT spokesman told OUT-LAW that this system provides enough security to protect network sharers. "This provides traceability," said the spokesman. "The person logging on to the publicly available side of someone's network has to use their own login details. We can track them back, we can tell that it is not the home user doing illegal activity."
BT's three million broadband customers will be invited to join the Fon network, which means that in return for sharing a portion of their broadband connection they are given free access to shared networks using Fon routers all over the world.
The company claims that there are 190,000 such shared networks across the world. "The revolutionary idea for a massive Wi-Fi community built by individual people and not a large corporate enterprise marks BT’s boldest step yet in building extensive broadband coverage outside of the home or office," said a BT statement.
The deal with Fon involves an investment by BT in the company, whose other investors include Google. BT will have a seat on the board of Fon.
An OUT-LAW investigation last year found that seven of the UK's top 10 internet service providers banned the sharing of connectivity. BT was one of those.
The BT spokesman said, though, that its new service is far more secure than the act of simply opening up a network to any user without any identification.
"This is better than the situation if you don't have a password protected wireless router and your network is unsecured, which means that people can log on, use your IP address and you get the blame if they carry out illegal activity," he said.
One wireless security expert has concerns about the system, though. Andy Cuff is managing director of wireless security consultancy Computer Network Defence.
"I have some issues with security, with the segregation of data, ensuring that information is truly segregated between the guest and the owner of the network," said Cuff, who said that much depends on the exact technology BT and Fon are using.
"Other issues are ensuring the authentication and audit: with the best will in the world, if someone is using your network to look at dodgy material, despite them having some sort of mechanism in place to identify the original source, is it sufficient for police to say 'that's a Fon user' or will they kick your door down first of all and look into it retrospectively?"
"If I was using it I wouldn't subscribe until it had been in place for a considerable amount of time to allow other people to have a crack at it," said Cuff.