The Census Bureau is mandated by the U.S. constitution to complete a count of the population every decade. Few realize however, that Title 13, Sec. 9 of the U.S. Code also requires the Bureau to "keep personally identifiable information confidential for 72 years." With the growth of Big Data, this privacy mandate has become a much more complicated task, thanks to "database reconstruction," a method of partially reconstructing a private dataset from public aggregate information. Consider the well-known example below of how one data scientist obtained former Governor William Weld's medical history from aggregate data released to the Massachusetts Group…