Carnivore was the official name for a custom-built Internet surveillance system used by the FBI from around 1997 through the end of 2004. The original software system was no longer in use by 2005; however, the program does continue using commercially available software.
Carnivore was an advanced packet-sniffing system that could isolate communications between two parties on the Internet or could monitor the activities of a targeted user. A packet sniffer is a tool that sifts through the millions of communications on the web by looking for certain patterns in the data streams. Internet pirates commonly use packet sniffers to looks for unencrypted credit card numbers and other personal information transmitted on web, which is why it is never a good idea to use a web site that does not use the https (secure socket layers) technology to encrypt personal data.
A packet sniffer is a commonly used Internet tool, but what set Carnivore apart was the ability to filter the data more precisely to avoid picking up other communications that the FBI could not legally view. The Carnivore systems used a PC installed at an ISP (Internet Service Provider) through which the communication that the FBI wanted to monitor flowed.
So what did the system monitor? Carnivore could monitor e-mail communications and could reconstruct any web page that a targeted user was viewing. Eventually the system could monitor a user’s activities in real time. The system was used primarily to monitor the Internet activities of terrorists and people known to be communicating with terrorists. In many cases, a wire tap warrant was obtained through a judge when it was determined that a full surveillance of a suspect was necessary. The FBI did report their activities to Congressional and Senate oversight committees, who monitored the activities to assure that the system was not being misused. Specific terrorist targets were identified and only those targets were supposed to be monitored. The FBI reported the use of Carnivore approximately 25 times from 1998 through 2000, and even fewer times beyond that. These numbers only document the times when the FBI’s systems were used for terrorist surveillance, and not situations where an ISP used their own systems to cooperate with the FBI.
The Carnivore system was eventually renamed DCS-1000. By 2005, the original Carnivore/DCS-1000 system was no longer used, but the surveillance program itself was not discontinued. The program is believed to still be in use using off-the-shelf systems that have evolved to where they meet the needs of the FBI.