Computer surveillance programs are widespread today, and almost all Internet traffic is closely monitored for clues of illegal activity.
Supporters[who?] say that watching all Internet traffic is important, because by knowing everything that everyone is reading and writing, they can identify terrorists and criminals, and protect society from them.
Opponents, including digital rights organizations such as the Electronic Frontier Foundation, cite concerns over individual privacy, freedom of speech, innovation, and consumer rights as justification for backing litigation against pro-surveillance policy. Others[who?] consider the possibility of a totalitarian state where political dissent is impossible and opponents of state policy are removed in COINTELPRO-like purges. Such a state may be referred to as an Electronic Police State, in which the government aggressively uses electronic technologies to record, organize, search and distribute forensic evidence against its citizens. The hacktivist group Anonymous has hacked into government websites in protest of what it considers "draconian surveillance".
Network surveillance 
The vast majority of computer surveillance involves the monitoring of data and traffic on the Internet. In the United States for example, under the Communications Assistance For Law Enforcement Act, all phone calls and broadband internet traffic (emails, web traffic, instant messaging, etc.) are required to be available for unimpeded real-time monitoring by Federal law enforcement agencies.
Packet capture (also sometimes referred to as “packet sniffing”) is the monitoring of data traffic on a computer network. Computers communicate over the Internet by breaking up messages (emails, images, videos, web pages, files, etc.) into small chunks called "packets", which are routed through a network of computers, until they reach their destination, where they are assembled back into a complete "message" again. Packet Capture Appliance intercepts these packets as they are travelling through the network, in order to examine their contents using other programs. A packet capture is an information gathering tool, but not an analysis tool. That is it gathers "messages" but it does not analyze them and figure out what they mean. Other programs are needed to perform traffic analysis and sift through intercepted data looking for important/useful information. Under the Communications Assistance For Law Enforcement Act all U.S. telecommunications providers are required to install packet sniffing technology to allow Federal law enforcement and intelligence agencies to intercept all of their customers' broadband Internet traffic.
There is far too much data gathered by these packet sniffers for human investigators to manually search through all of it. So automated Internet surveillance computers sift through the vast amount of intercepted Internet traffic, and filter out and report to human investigators those bits of information which are "interesting"—such as the use of certain words or phrases, visiting certain types of web sites, or communicating via email or chat with a certain individual or group. Billions of dollars per year are spent, by agencies such as the Information Awareness Office, NSA, and the FBI, to develop, purchase, implement, and operate systems which intercept and analyze all of this data, and extract only the information which is useful to law enforcement and intelligence agencies.
Similar systems are now operated by Iranian secret police to identify and suppress dissidents. All required hardware and software has been allegedly installed by German Siemens AG and Finnish Nokia 
Corporate surveillance 
Corporate surveillance of computer activity is very common. The data collected is most often used for marketing purposes or sold to other corporations, but is also regularly shared with government agencies. It can be used as a form of business intelligence, which enables the corporation to better tailor their products and/or services to be desirable by their customers. Or the data can be sold to other corporations, so that they can use it for the aforementioned purpose. Or it can be used for direct marketing purposes, such as targeted advertisements, where ads are targeted to the user of the search engine by analyzing their search history and emails (if they use free webmail services), which is kept in a database.
For instance, Google, the world's most popular search engine, stores identifying information for each web search. An IP address and the search phrase used are stored in a database for up to 18 months. Google also scans the content of emails of users of its Gmail webmail service, in order to create targeted advertising based on what people are talking about in their personal email correspondences. Google is, by far, the largest Internet advertising agency—millions of sites place Google's advertising banners and links on their websites, in order to earn money from visitors who click on the ads. Each page containing Google advertisements adds, reads, and modifies "cookies" on each visitor's computer. These cookies track the user across all of these sites, and gather information about their web surfing habits, keeping track of which sites they visit, and what they do when they are on these sites. This information, along with the information from their email accounts, and search engine histories, is stored by Google to use to build a profile of the user to deliver better-targeted advertising.
The United States government often gains access to these databases, either by producing a warrant for it, or by simply asking. The Department of Homeland Security has openly stated that it uses data collected from consumer credit and direct marketing agencies for augmenting the profiles of individuals that it is monitoring.
Malicious software 
In addition to monitoring information sent over a computer network, there is also a way to examine data stored on a computer's hard drive, and to monitor the activities of a person using the computer. A surveillance program installed on a computer can search the contents of the hard drive for suspicious data, can monitor computer use, collect passwords, and/or report back activities in real-time to its operator through the Internet connection.
There are multiple ways of installing such software. The most common is remote installation, using a backdoor created by a computer virus or trojan. This tactic has the advantage of potentially subjecting multiple computers to surveillance. Viruses often spread to thousands or millions of computers, and leave "backdoors" which are accessible over a network connection, and enable an intruder to remotely install software and execute commands. These viruses and trojans are sometimes developed by government agencies, such as CIPAV and Magic Lantern. More often, however, viruses created by other people or spyware installed by marketing agencies can be used to gain access through the security breaches that they create.
Another method is "cracking" into the computer to gain access over a network. An attacker can then install surveillance software remotely. Servers and computers with permanent broadband connections are most vulnerable to this type of attack.
One can also physically place surveillance software on a computer by gaining entry to the place where the computer is stored and install it from a compact disc, floppy disk, or thumbdrive. This method shares a disadvantage with hardware devices in that it requires physical access to the computer.
Social network analysis 
One common form of surveillance is to create maps of social networks based on data from social networking sites as well as from traffic analysis information from phone call records such as those in the NSA call database, and internet traffic data gathered under CALEA. These social network "maps" are then data mined to extract useful information such as personal interests, friendships & affiliations, wants, beliefs, thoughts, and activities.
Many U.S. government agencies such as the Defense Advanced Research Projects Agency (DARPA), the National Security Agency (NSA), and the Department of Homeland Security (DHS) are currently investing heavily in research involving social network analysis. The intelligence community believes that the biggest threat to the U.S. comes from decentralized, leaderless, geographically dispersed groups. These types of threats are most easily countered by finding important nodes in the network, and removing them. To do this requires a detailed map of the network.
Jason Ethier of Northeastern University, in his study of modern social network analysis, said the following of the Scalable Social Network Analysis Program developed by the Information Awareness Office:
The purpose of the SSNA algorithms program is to extend techniques of social network analysis to assist with distinguishing potential terrorist cells from legitimate groups of people ... In order to be successful SSNA will require information on the social interactions of the majority of people around the globe. Since the Defense Department cannot easily distinguish between peaceful citizens and terrorists, it will be necessary for them to gather data on innocent civilians as well as on potential terrorists.—Jason Ethier
Monitoring from a distance 
It has been shown that it is possible to monitor computers from a distance, with only commercially available equipment, by detecting the radiation emitted by the CRT monitor. This form of computer surveillance, known as TEMPEST, involves reading electromagnetic emanations from computing devices in order to extract data from them at distances of hundreds of meters.
IBM researchers have also found that, for most computer keyboards, each key emits a slightly different noise when pressed. The differences are individually identifiable under some conditions, and so it's possible to log key strokes without actually requiring logging software to run on the associated computer.
Policeware is software designed to police citizens by monitoring discussion and interaction of its citizens. Within the U.S., Carnivore was a first incarnation of secretly installed e-mail monitoring software installed in Internet service providers' networks to log computer communication, including transmitted e-mails. Magic Lantern is another such application, this time running in a targeted computer in a trojan style and performing keystroke logging. Oasis, software developed by Central Intelligence Agency (CIA), is designed for converting intercepted audio into searchable text. CIPAV, deployed by FBI, is a spyware/trojan allegedly designed for identification of a computer.
The CBDTPA for "Consumer Broadband and Digital Television Promotion Act" was a bill proposed in the United States Congress. The CBDTPA was known as the "SSSCA" while in draft form, and was killed in committee in 2002. Had the CBDTPA become law, it would have prohibited technology that read digital content (such as music, video, and e-books) without Digital Rights Management (DRM) that prevented access to this material without the permission of the copyright holder.
Surveillance as an aid to censorship 
Surveillance and censorship are different. Surveillance can be preformed without censorship, but it is harder to engage in censorship without some form of surveillance. And even when surveillance does not lead directly to censorship, the widespread knowledge or belief that a person, their computer, or their use of the Internet is under surveillance can lead to self-censorship.
In March 2013 Reporters Without Borders issued a Special report on Internet surveillance that examines the use of technology that monitors online activity and intercepts electronic communication in order to arrest journalists, citizen-journalists, and dissidents. The report includes a list of "State Enemies of the Internet", Bahrain, China, Iran, Syria, and Vietnam, countries whose governments are involved in active, intrusive surveillance of news providers, resulting in grave violations of freedom of information and human rights. Computer and network surveillance is on the increase in these countries. The report also includes a second list of "Corporate Enemies of the Internet", Amesys (France), Blue Coat Systems (U.S.), Gamma (UK and Germany), Hacking Team (Italy), and Trovicor (Germany), companies that sell products that are liable to be used by governments to violate human rights and freedom of information. Neither list is exhaustive and they will be expanded in the coming months.
Protection of sources is no longer just a matter of journalistic ethics; it increasingly also depends on the journalist’s computer skills and all journalists should equip themselves with a “digital survival kit” if they are exchanging sensitive information online or storing it on a computer or mobile phone. And individuals associated with high profile rights organizations, dissident, protest, or reform groups are urged to take extra precautions to protect their online identities.
See also 
- Anonymizer, a software system that attempts to make network activity untraceable
- Computer and Internet Protocol Address Verifier (CIPAV)
- Computer surveillance in the workplace
- Differential privacy
- Carnivore, a U.S. Federal Bureau of Investigation system to monitor email and electronic communications
- [Publicly Available Spy Software
- GhostNet, a large-scale cyber spying operation discovered in March 2009
- Magic Lantern, keystroke logging software developed by the U.S. Federal Bureau of Investigation
- ECHELON, a signals intelligence (SIGINT) collection and analysis network operated on behalf of Australia, Canada, New Zealand, the United Kingdom, and the United States, also known as AUSCANNZUKUS and Five Eyes
- NSA call database
- TEMPEST, codename for studies of unintentional intelligence-bearing signals which, if intercepted and analyzed, may disclose the information transmitted, received, handled, or otherwise processed by any information-processing equipment
- Total Information Awareness
-  Retrieved 19 April 2013
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