Consumer Law

Online (Non) Privacy

By Brian Wolfman

Today's New York Times explains "How Privacy Vanishes Online."  Among other things, the article explains how, by combining information from a variety of sources, someone can correctly "guess" a lot of people's social security numbers:

Even more unnerving to privacy advocates is the work of two researchers from Carnegie Mellon University. In a paper published last year, Alessandro Acquisti and Ralph Gross reported that they could accurately predict the full, nine-digit Social Security numbers for 8.5 percent of the people born in the United States between 1989 and 2003 ? nearly five million individuals.

Social Security numbers are prized by identity thieves because they are used both as identifiers and to authenticate banking, credit card and other transactions.

The Carnegie Mellon researchers used publicly available information from many sources, including profiles on social networks, to narrow their search for two pieces of data crucial to identifying people ? birthdates and city or state of birth.

That helped them figure out the first three digits of each Social Security number, which the government had assigned by location. The remaining six digits had been assigned through methods the government didn?t disclose, although they were related to when the person applied for the number. The researchers used projections about those applications as well as other public data, like the Social Security numbers of dead people, and then ran repeated cycles of statistical correlation and inference to partly re-engineer the government?s number-assignment system.

Full post as published by CL&P Blog on March 17, 2010 (boomark / email).