One of the notable concepts to emerge from Apple’s World Wide Developers Conference in San Francisco this year, has been the notion of differential privacy. As Wired puts it Differential Privacy is the “…statistical science of trying to learn as much as possible about a group while learning as little as possible about any individual in it.”
Let’s say you wanted to count how many of your online friends were dogs, while respecting the maxim that, on the Internet, nobody should know you’re a dog. To do this, you could ask each friend to answer the question “Are you a dog?” in the following way. Each friend should flip a coin in secret, and answer the question truthfully if the coin came up heads; but, if the coin came up tails, that friend should always say “Yes” regardless.
Then you could get a good estimate of the true count from the greater-than-half fraction of your friends that answered “Yes”. However, you still wouldn’t know which of your friends was a dog: each answer “Yes” would most likely be due to that friend’s coin flip coming up tails. (source: Google)
The premise of differential privacy lies in that the reports are indistiguishable, the random coin flips have no unique identifiers, yet the aggregation of reports allow us to share common results shared by many users. With companies like Facebook and Google constantly receiving flack for compromising user privacy in lieu of the value of selling customer insights, and user-targeted advertising, Apple are more-or-less perceived as the beacon when it comes to championing user privacy. Differential Privacy is Apple’s answer as the industry embeds itself more and more inmobile and wearable renaissance, especially with location-capable devices making privacy-invasiveness more frequent.
Read more at Doron Katz.