When Big Data becomes Big Brother

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Media captionRory Cellan-Jones with John McAfee

We live in the social mobile era, where we all collect and share vast amounts of data about ourselves and others.

By handing over that data to corporations and governments we are promised great benefits in everything from our health and our wealth to our safety from criminals. But of course there are dangers too and I've been hearing some horror stories about when Big Data becomes Big Brother.

The first was from one of the technology industry's more colourful figures. John McAfee, who is in London this week for the Infosecurity Europe conference, is the man who virtually invented the anti-virus industry. He sold his stake in McAfee more than 20 years ago and has since had numerous adventures, culminating in his flight from Belize in 2012 after police in the Central American state tried to question him about a murder. He was described by Belize's prime minister at the time as "extremely paranoid, even bonkers".

So, perhaps not surprising, that the Infosecurity crowd who gathered to hear him speak were treated to dire warnings about the threat to their security from two sources - their mobile phones and their governments.

But of course just because you are paranoid it does not mean they are not out to get you, and when I meet John McAfee after his speech he gives a perfectly coherent account of why we should be worried. We are now all carrying around smartphones, he explains, but security has not caught up with the fact that they are very advanced computers which can be used to spy on us if we install any number of untested apps that may have been created by people with criminal intent.

But it's government spying on those phones that really worries him. He cheers the brake which the Senate applied to the US government's surveillance powers at the weekend, but fears that in Britain no such limits are in place.

In particular, he rails against any attempt to try to crack the encryption that protects many personal messages. When I suggest that there might be a need to know what criminals and terrorists are planning, he bats that away: "We have lived with criminals for ever - does that mean we should all have to suffer?"

He compares encryption with whispering a message in your wife's ear and asks whether we would have thought it justified years ago to ban whispering. "If it sounds insane for government to say you are not allowed to whisper to your wife - it is insane." And he says the big technology companies should have the courage to stand up to governments on this issue: "If enough people stand up the government will back down."

When I suggest delicately that his colourful past might make people disinclined to take him seriously, he bats that straight back at me. "My colourful life implies that I've done some serious things," he says, explaining that his experiences in Belize have shown him just how dangerous a rogue government can be.

You can hear my interview with John McAfee on Tech Tent, which this week comes live from the Cheltenham Science Festival. Here too, the question of what we are doing with our data has been a major theme.

Last night I was the moderator at an event called Big Data, Big Brother, where the panel expressed their worries about the uses to which our data could be put, in front of an audience which shared their fears. The lawyer Marion Oswald mentioned the Samaritans' Radar Twitter app as an example of where public data posted by people who might or might not have been suicidal could have been used in a questionable way without their consent.

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A software engineer Martyn Thomas advised us to be wary of claims that data was anonymised, explaining how easy it was to identify someone once you had pieced together just a few data points. Here in the home of GCHQ, the audience seemed more concerned about corporate surveillance than government spies, and many were enthusiastic about ad-blocking software and other means of throwing the likes of Google off your trail.

But afterwards in the more relaxed setting of the Festival's Ideas Cafe, data scientists from Warwick University reminded us of the positive aspects of their work. I sat at a table where a computer scientist explained how he was mapping London to spot which areas should be targeted for diabetes prevention measures. He was using data from a variety of sources, including a credit rating agency, to examine lifestyles and hence vulnerability to Type 2 diabetes.

While some will be concerned about how medical and financial data are combined in this way, many will see the benefits of applying data science to this kind of task. As the Big Data gold rush continues, lawyers, ethicists and consumer groups are all going to have their work cut out to help us get a good balance between the risks and rewards of crunching the numbers.