Official use The contracts or licenses by which the state controls
telephone companies often require that the companies must provide access to tapping lines to law enforcement. In the U.S., telecommunications carriers are required by law to cooperate in the interception of communications for law enforcement purposes under the terms of
Communications Assistance for Law Enforcement Act (CALEA). When
telephone exchanges were mechanical, a tap had to be installed by technicians, linking circuits together to route the audio signal from the call. Now that many exchanges have been converted to digital technology, tapping is far simpler and can be ordered remotely by computer. This central office switch wiretapping technology using the Advanced Intelligent Network (AIN) was invented by Wayne Howe and Dale Malik at BellSouth's Advanced Technology R&D group in 1995 and was issued as US Patent #5,590,171.
Telephone services provided by
cable TV companies also use digital switching technology. If the tap is implemented at a
digital switch, the switching computer simply copies the digitized bits that represent the phone conversation to a second line and it is impossible to tell whether a line is being tapped. A well-designed tap installed on a phone wire can be difficult to detect. In some places, some law enforcement may be able to even access a mobile phone's internal microphone even while it isn't actively being used on a phone call (unless the battery is removed or drained). The noises that some people believe to be telephone taps are simply
crosstalk created by the
coupling of signals from other phone lines. Data on the calling and called number, time of call and duration, will generally be collected automatically on all calls and stored for later use by the
billing department of the phone company. These data can be accessed by security services, often with fewer legal restrictions than for a tap. This information used to be collected using special equipment known as
pen registers and
trap and trace devices and U.S. law still refers to it under those names. Today, a list of all calls to a specific number can be obtained by sorting billing records. A telephone tap during which only the call information is recorded but not the contents of the phone calls themselves, is called a
pen register tap. For telephone services via digital exchanges, the information collected may additionally include a log of the type of communications media being used (some services treat data and voice communications differently, in order to conserve bandwidth).
Non-official use connects to the wall socket while the phone being monitored is connected to the adapter's socket. The
audio plug connects to the recording device (computer, tape recorder, etc.). Conversations can be recorded or monitored unofficially, either by tapping by a third party without the knowledge of the parties to the conversation or recorded by one of the parties. This may or may not be illegal, according to the circumstances and the jurisdiction. There are a number of ways to monitor telephone conversations. One of the parties may record the conversation, either on a tape or solid-state recording device, or they may use a computer running
call recording software. The recording, whether overt or covert, may be started manually, automatically when it detects sound on the line (
VOX), or automatically whenever the phone is off the hook. • using an inductive
coil tap (telephone pickup coil) attached to the handset or near the base of the telephone, picking up the stray field of the
telephone's hybrid; • fitting an in-line tap, as discussed below, with a recording output; • using an in-ear microphone while holding the telephone to the ear normally; this picks up both ends of the conversation without too much disparity between the volumes • more crudely and with lower quality, simply using a speakerphone and recording with a normal microphone The conversation may be monitored (listened to or recorded) covertly by a third party by using an
induction coil or a direct electrical connection to the line using a
beige box. An induction coil is usually placed underneath the base of a telephone or on the back of a telephone handset to pick up the signal inductively. An electrical connection can be made anywhere in the telephone system, and need not be in the same premises as the telephone. Some apparatus may require occasional access to replace batteries or tapes. Poorly designed tapping or transmitting equipment can cause interference audible to users of the telephone. The tapped signal may either be recorded at the site of the tap or transmitted by radio or over the telephone wires. state-of-the-art equipment operates in the 30–300 GHz range to keep up with telephone technology compared to the 772 kHz systems used in the past. The transmitter may be powered from the line to be maintenance-free, and only transmits when a call is in progress. These devices are low-powered as not much power can be drawn from the line, but a state-of-the-art receiver could be located as far away as ten kilometers under ideal conditions, though usually located much closer. Research has shown that a
satellite can be used to receive terrestrial
transmissions with a power of a few milliwatts. Any sort of radio transmitter whose presence is suspected is detectable with suitable equipment. Conversation on many early
cordless telephones could be picked up with a simple
radio scanner or sometimes even a domestic radio. Widespread digital
spread spectrum technology and
encryption has made eavesdropping increasingly difficult. A problem with recording a telephone conversation is that the recorded volume of the two speakers may be very different. A simple tap will have this problem. An in-ear microphone, while involving an additional distorting step by converting the electrical signal to sound and back again, in practice gives better-matched volume. Dedicated, and relatively expensive, telephone recording equipment equalizes the sound at both ends from a direct tap much better.
Location data Mobile phones are, in
surveillance terms, a major liability. For mobile phones the major threat is the collection of communications data. This data does not only include information about the time, duration, originator and recipient of the call, but also the identification of the base station where the call was made from, which equals its approximate geographical location. This data is stored with the details of the call and has utmost importance for
traffic analysis. It is also possible to get greater resolution of a phone's location by combining information from a number of cells surrounding the location, which cells routinely communicate (to agree on the next handoff—for a moving phone) and measuring the
timing advance, a correction for the speed of light in the
GSM standard. This additional precision must be specifically enabled by the telephone company—it is not part of the network's ordinary operation.
Internet In 1995,
Peter Garza, a Special Agent with the
Naval Criminal Investigative Service, conducted the first court-ordered Internet wiretap in the United States while investigating Julio Cesar "Griton" Ardita. As technologies emerge, including
VoIP, new questions are raised about law enforcement access to communications (see
VoIP recording). In 2004, the
Federal Communications Commission was asked to clarify how the
Communications Assistance for Law Enforcement Act (CALEA) related to Internet service providers. The FCC stated that “providers of broadband Internet access and voice over Internet protocol (“VoIP”) services are regulable as “telecommunications carriers” under the Act.” Those affected by the Act will have to provide access to law enforcement officers who need to monitor or intercept communications transmitted through their networks. As of 2009, warrantless surveillance of internet activity has consistently been upheld in
FISA court. The
Internet Engineering Task Force has decided not to consider requirements for wiretapping as part of the process for creating and maintaining IETF standards. Typically, illegal Internet wiretapping is conducted via
Wi-Fi connection to someone's Internet by cracking the
WEP or
WPA key, using a tool such as
Aircrack-ng or
Kismet. Once in, the intruder relies on a number of potential tactics, for example an
ARP spoofing attack, allowing the intruder to view
packets in a tool such as
Wireshark or
Ettercap.
Mobile phone The first generation mobile phones ( through 1990) could be easily monitored by anyone with a
'scanning all-band receiver' because the system used an analog transmission system-like an ordinary radio transmitter. Instead, digital phones are harder to monitor because they use digitally encoded and compressed transmission. However the government can tap mobile phones with the cooperation of the phone company. It is also possible for organizations with the correct technical equipment to monitor mobile phone communications and decrypt the audio. To the mobile phones in its vicinity, a device called an "
IMSI-catcher" pretends to be a legitimate base station of the mobile phone network, thus subjecting the communication between the phone and the network to a
man-in-the-middle attack. This is possible because, while the mobile phone has to authenticate itself to the mobile telephone network, the network does not authenticate itself to the phone. There is no defense against IMSI-catcher based eavesdropping, except using end-to-end call encryption; products offering this feature,
secure telephones, are already beginning to appear on the market, though they tend to be expensive and incompatible with each other, which limits their proliferation.
Webtapping Logging the
IP addresses of users that access certain websites is commonly called "webtapping". Webtapping is used to monitor websites that presumably contain dangerous or sensitive materials, and the people that access them. It is allowed in the US by the
Patriot Act, but is considered a questionable practice by many.
Telephone recording In Canada, anyone is legally allowed to record a conversation as long as they are involved in the conversation. The police must apply for a warrant beforehand to legally eavesdrop on a conversation, which requires that it is expected to reveal evidence to a crime. State agents may record conversations, but must obtain a warrant to use them as evidence in court. ==History==