Electronic Products Word of the Week: Wiretapping

With the revelation that what we do on the Internet is intensely watched by the federal government under a program called PRISM, it will be well worth our while to explore the electronics behind the generic form of snooping: wiretapping.

According to the Privacy Rights Clearinghouse, “wiretapping is any interception of a telephone transmission by accessing the telephone signal itself. Electronic eavesdropping is the use of an electronic transmitting or recording device to monitor conversations without the consent of the parties.”

Federal wiretap laws apply to oral, wire, and electronic communications, but not silent video communications, such as webcams or other video monitoring without an audio component. The Communications Assistance for Law Enforcement Act (CALEA), also known as the Digital Telephony Act, was passed by Congress in October 1994. Digital communications services generally convert telephone conversations and other transmissions to a digital code that is impossible to “listen in” on. The Privacy Rights Clearinghouse points out that “the Digital Telephony Act requires all telephone companies to make digital communications available to law enforcement officials in the same way that traditional voice transmissions are currently accessible.” So the government has for some time had the right to listen in, even as we use the Internet.

There are five types of wiretap devices. Any of these methods constitute electronic surveillance:

1. An acoustic bug is the placing of a water glass, stethoscope, or rubber tube into an area and directly intercepting the communication with the naked ear
2. An ultrasonic or VLF bug can be placed in a room like a radio frequency bug, except that it transmits a different type of signal. The sound is converted into an audio signal above the typical range of human hearing. It is then intercepted from a close-by location and converted back to its original audio signal. This makes the device more difficult to detect and more expensive.
3. An RF (or radio frequency) Bug is the most-well-known type of bugging device. A radio transmitter is placed in an area or in a device.
4. An optical bug converts sound into an optical pulse or beam of light. Because they are highly expensive and very easy to detect, optical bugs are rarely used. Examples of optical bugs include active and passive laser listening devices.
5. A hybrid bug is a combination of any of the four previous types.

Aside from these types of bugs, two other devices are used in electronic surveillance.

1. A “pen register” is a device that records numbers dialed out on the telephone line to which it is attached.
2. “Tap detectors” may be able to detect someone “listening in” by picking up an extension phone, and may be able to detect someone cutting a telephone line.  However, neither of these occurrences may be considered a “wiretap,” strictly speaking, and neither of these occurrences is necessary in order for someone to connect a wiretap to your line.  Those with experience in telephone technology advise consumers to disregard the claims of companies that sell “tap detectors.

The determined eavesdropper will find a variety of sophisticated electronic surveillance and listening devices on the market. Also, radio scanners are available which can monitor cordless and cellular phone conversations, baby monitors and home intercom systems, especially older devices that use analog technology rather than digital signals Long-distance calls which travel by microwave or satellite links are also susceptible to monitoring.

The Privacy Rights Clearinghouse points out that most wiretapping devices emit no audible sounds. If you hear others talking on your phone, you may simply be experiencing “crosstalk,” a common phone problem that is simply unwanted signals in a communication channel, whether intelligible or unintelligible. For example, cordless telephones may pick up others' conversations when two cordless phones are tuned to the same channel.

 Most Internet protocol (IP) communications do not behave as telephone calls. Peer-to-peer voice over IP (VoIP) systems use a centralized mechanism to provide the communicating parties with each other's IP addresses, but rely on the Internet for actual communication. Thus, there is no central point at which a wiretap could be authorized.