The technology, named “Carnivore”, allows the interception and analysis of vast quantities of e-mail by scanning all e-mails passing through an ISP to identify messages that may help with criminal investigations.
The American Civil Liberties Union has expressed its belief that Carnivore infringes ISP and user privacy rights, and it claims that Carnivore should be subject to similar regulations as those imposed on wiretaps.
It bases its argument on the 4th Amendment of the US Constitution which prohibits unreasonable searches and seizures of an individual's papers and effects without probable cause.
A fundamental concern appears to be that the government has exclusive control of the Carnivore system unlike wiretapping technology which is maintained by independent telephone companies. This is compounded by the amount of information that Carnivore can pick up on.
However, the main concern according to James Dempsey of the Centre of Democracy and Technology, is that the true nature of Carnivore remains unknown. He commented that “the FBI is placing a black box inside the computer network of an ISP...not even the ISP knows exactly what that gizmo is doing”.