While the draft regulation calls for the data made available to researchers to be made anonymous, it is very hard to anonymize data sufficiently, Anderson said.

"That's something that we geeks have known for thirty years," Anderson told the audience.

By querying a database often and asking it different questions it is possible to find out where someone lives, or to find the medical record of a colleague or friend.

"You can always find a set of queries that reveals the target," he said.

When it comes to making data anonymous, Anderson said, "The big practical problem is context." For example, he said he could find out more about a particular colleague by querying the database for 42-year-old women in the U.K. with a 9-year-old daughter, who both have psoriasis.