A database of this information from 191 million voter records was posted online over the last week, the latest example of voter data becoming freely available, alarming privacy experts who say the information can be used for phishing attacks, identity theft and extortion. The information is no longer publicly accessible.

It is not known who built the database, where all the data came from, and whether its disclosure resulted from an inadvertent release or from hacks. The disclosure was discovered by an information technology specialist, Chris Vickery, and the findings were published on databreaches.net. The federal authorities were alerted to possible concerns about security and the legality of what was done…

Big data advocates argue that what is in most voter files is nothing more than the White Pages of a phone book augmented with party affiliation and voting history (not which candidate people voted for, but whether they voted.) But for privacy experts, that alone, especially when compiled in one place, is cause for concern.

“Simply by digitizing the data, collecting it in one place, making it freely available in one place — it’s a Christmas gift for thieves,” said Neal O’Farrell, the executive director of the Identity Theft Council. “I interviewed an identity thief, and he said credit card numbers are for chumps. It’s much easier to get caught. The cybercriminals really want to know who you are. And voter information and any kind of information that fills in all the blanks makes it easier for phishing, for social engineering, and for extortion.”