Scientists have developed a new data smuggling software which they say could allow citizens in countries like China having strict Internet filters to visit any site they want. The software,called Telex,hides data from banned websites inside traffic from sites deemed safe. It draws on well-known encryption techniques to conceal data making it hard to decipher. So far,Telex is only a prototype but in tests it has been able to defeat Chinese web filters,the researchers said. We have tried it from within China bouncing it off computers there. So far,we have had no problems with the censorship there," Dr Alex Halderman,one of developers of Telex,was quoted as saying by the BBC. The software allowed the team to view banned content such as high definition YouTube videos and sites deemed subversive by the Chinese authorities,he said. According to Dr Halderman,Telex was developed to get around the problem that stops other anti-censorship technologies being more effective. Many existing anti-censorship systems involve connecting to a server or network outside the country in which a user lives. This approach relies on spreading information about these servers and networks widely enough that citizens hear about them but not so much that censors can find out and block them. Telex turns this approach on its head,said Dr Halderman. Instead of having some server outside the network that's participating we are doing it in the core of the network," he said. According to its developers,Telex exploits the fact that few net-censoring nations block all access and most are happy to let citizens visit a select number of sites regarded as safe. When a user wants to visit a banned site they initially point their web browser at a safe site. As they connect,Telex software installed on their PC puts a tag or marker on the data stream being sent to that safe destination. Net routers outside the country recognise that the data stream has been marked and re-direct a request to a banned site. Data from censored webpages is piped back to the user in a data stream disguised to resemble that from safe sites. The data stream is subtly altered using a well-known encryption technique,called public key cryptography,which allows anyone with a public key to lock content but only allows the owner of the corresponding private key to unlock it. Although Telex was "not ready" for real users,Dr Halderman said the development team had been using it for their own web browsing for months. In addition,he said,the team had carried out some small scale tests against sophisticated filtering systems. One stumbling block for Telex was getting the basic software to users without it being compromised by net censors who could add spyware or key loggers to it,said Dr Halderman. There were other issues to be resolved as development continues,he added.
