The FBI appears to have adopted an invasive Internet surveillance technique that collects far more data on innocent Americans than previously has been disclosed.
Instead of recording only what a particular suspect is doing, agents conducting investigations appear to be assembling the activities of thousands of Internet users at a time into massive databases, according to current and former officials. That database can subsequently be queried for names, e-mail addresses or keywords.
[...] Call it the vacuum-cleaner approach. It’s employed when police have obtained a court order and an Internet service provider can’t “isolate the particular person or IP address” because of technical constraints, says Paul Ohm, a former trial attorney at the Justice Department’s Computer Crime and Intellectual Property Section. (An Internet Protocol address is a series of digits that can identify an individual computer.)
In a telephone conversation afterward, Ohm said that full-pipe recording has become federal agents’ default method for Internet surveillance. “You collect wherever you can on the (network) segment,” he said. “If it happens to be the segment that has a lot of IP addresses, you don’t throw away the other IP addresses. You do that after the fact.”
“You intercept first and you use whatever filtering, data mining to get at the information about the person you’re trying to monitor,” he added.