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Deep Packet Inspection by governments

See also: network surveillance and censorship

In addition to using DPI for the security of their own networks, governments in North America, Europe and Asia use DPI for various purposes such as surveillance and censorship; many of these programs are classified.^[15]

[edit] United States

Main article: NSA warrantless surveillance controversy

The NSA, with cooperation from AT&T has used Deep Packet Inspection technology to make internet traffic surveillance, sorting and forwarding more intelligent. The DPI is used to find which packets are carrying e-mail or a Voice over Internet Protocol (VoIP) phone call.^[16] Traffic associated with AT&T’s Common Backbone was "split" between two fibers, dividing the signal so that 50 percent of the signal strength went to each output fiber. One of the output fibers was diverted to a secure room; the other carried communications on to AT&T’s switching equipment. The secure room contained Narus traffic analyzers and logic servers; Narus states that such devices are capable of real-time data collection (recording data for consideration) and capture at 10 gigabits per second. Certain traffic was selected and sent over a dedicated line to a "central location" for analysis. According to Marcus’s affidavit, the diverted traffic "represented all, or substantially all, of AT&T’s peering traffic in the San Francisco Bay area," and thus, "the designers of the ... configuration made no attempt, in terms of location or position of the fiber split, to exclude data sources comprised primarily of domestic data."^[17] Narus's Semantic Traffic Analyzer software which runs on IBM or Dell Linux servers, using DPI technology, sorts through IP traffic at 10Gbit/s to pick out specific messages based on a targeted e-mail address, IP address or, in the case of VOIP, phone number.^[18] President George W. Bush and Attorney General Alberto R. Gonzales have asserted that they believe the president has the authority to order secret intercepts of telephone and e-mail exchanges between people inside the United States and their contacts abroad without obtaining a FISA warrant.^[19]

The Defense Information Systems Agency has developed a sensor platform that uses Deep Packet Inspection.^[20]

[edit] China

Main article: Internet censorship in the People's Republic of China

The Chinese government uses Deep Packet Inspection to monitor and censor network traffic and content that it claims harmful to Chinese citizens or state interests. This material includes pornography, information on religion, and political dissent.^[21] People within China often find themselves blocked while accessing Web sites containing content related to Taiwanese and Tibetan independence, Falun Gong, the Dalai Lama, the Tiananmen Square protests and massacre of 1989, political parties that oppose that of the ruling Communist party, or a variety of anti-Communist movements.^[22] China also blocks VOIP traffic in and out of their country (though skype seems to work without problem),^[18] as well as visual media sites like YouTube.com and various photography and blogging sites.^[23]