May 2012

The Problem with Passwords

We use passwords all the time.  Sometimes they're called "PINs" or "access codes" or "lock combinations" but they amount to the same thing, a sequence of symbols that must be provided in order to get access to something.    Passwords have one big advantage: ease of use.  But this comes with several disadvantages.

Is aggregate data always private?

I have been writing recently about data and privacy.   Today I want to continue by talking about aggregate data.   A common intuitions is aggregate data--information averaged or summed over a large population--is inherently free of privacy implications.   As we'll see, that isn't always right.

What does it mean to preserve privacy?

In recent posts, I explained why hashing and pseudonyms often fail to provide anonymity.  These problems, and the well-known examples of people re-identifying supposedly anonymized data sets, might tempt you into believing that any data set can be re-identified given enough effort or that there is just no way to provide access to data in a privacy-preserving way.   But those conclus

Syncing and the FTC’s Myspace settlement

Today the FTC announced a proposed settlement with Myspace, on charges that the company broke its privacy promises to consumers. I want to focus today on one of the FTC's charges, relating to possible syncing of identifiers.

Myspace, a popular social network, assigns each of its users a numeric identifier called a "Friend ID". If you know someone's Friend ID, you can use it to get their public information, by accessing the URL<Friend ID>.