Cellular phone conversation easy prey for eavesdroppers

Aug 1, 1997 12:00 PM, SEAN HEYEN

Over the last decade, cellular phones have developed into one of the most convenient and reliable forms of portable communication available. People from every walk of life have begun to rely on portable phones to communicate important information.

Unfortunately, since they transmit conversations through the airwaves, cellular phones trade security for convenience.

Although digital methods of cellular communication - and their enhanced security - are on the horizon, the majority of domestic portable phones transmit an analog signal. The analog signal contains all the components of the conversation and can be intercepted without the caller's knowledge by listeners equipped even with rudimentary scanning equipment.

Currently, it is illegal in the United States to sell equipment designed specifically for scanning cellular calls. But the legislation has been enacted only recently, and there are no such laws forbidding the sale of cellular scanners in international markets. Consequently, millions of cellular scanners are in use in the United States. Laws have also been established to make the act of cellular eavesdropping illegal, but unwanted listeners rarely reveal the fact that they have intercepted key information. Therefore, eavesdroppers are virtually impossible to catch or prosecute without some prior knowledge of their illegal activities.

Three types of illegal listeners

Cellular eavesdroppers can be loosely categorized as recreational, moderately determined, and determined listeners, based on the quality of their scanning equipment and the intensity in which they use it to monitor cellular calls.

Recreational eavesdroppers are more likely to listen to general cellular traffic than to target a specific individual's communication. In many cases these people are equipped with low-cost scanning equipment that only allows them to monitor calls randomly. They spend a fair amount of free time with their scanner hopping from call to call for the sole purpose of entertainment. Although recreational listeners initially do not pose a major threat to cellular users, over time they may increase their technical knowledge and upgrade their equipment.

A moderately determined listener is usually equipped with better equipment and technical knowledge than the recreational listener. Many recreational listeners evolve into moderately determined listeners as they expand the scope of their hobby.

Using focused eavesdropping techniques, moderately determined listeners look for key information to gain an advantage over specific individuals. In order to scan a specific person's call, the eavesdropper must acquire some fairly sophisticated equipment. Depending on the features of the scanning equipment, it can become quite expensive.

Rather than spend money on a high-tier scanner, listeners in this classification sometimes opt for low-level scanning equipment accompanied by patienc e and persistence. Often, a patient eavesdropper with less sophisticated equipment can acquire as much sensitive information as an eavesdropper equipped with a high-level scanner. Ultimately, the moderately determined listener values intercepted information, but does not devote unlimited time and resources to tracking cellular phone calls.

Determined listeners, on the other hand, will spare no resource to track and intercept cellular calls. Most determined listeners are able to survey cellular communications constantly with equipment capable of tagging as many as 250 cellular phone numbers. When any of the 250 specified cell numbers begins to communicate, the scanner monitors and records its voice communication.

The scanner also has a tracking range of as many as five cell sites, allowing the listener to maintain surveillance as the caller moves through an area. With round-the-clock surveillance and the latest equipment, the determined listener is virtually guaranteed to intercept the desired cellular communication.

Protection from eavesdroppers

There are a few methods cellular users can employ to protect themselves from eavesdroppers. One of the easiest and most cost-effective methods is for cellular users to limit their portable communication to non-sensitive subject matter.

Discussion of sensitive issues should be conducted over a landline phone. Although the landline phone is not completely secure, it eliminates a large percentage of recreational and moderately determined listeners. Using a landline phone to discuss sensitive information is similar to locking your car when you leave it unattended. The locks cannot guarantee the safety of the car, but they will deter most potential thieves.

Digitally secure

Recently, more secure types of portable communication have been introduced to the market. Personal communication system (PCS) and digital cellular are two of the latest formats. These new formats use digital technology to transmit voice audio data. Since the digital phones send data rather than an analog signal, a standard analog scanner is unable to intercept the communication. The process of converting audio to data provides an element of security that analog cellular phones do not possess.

These new formats are not without limitations. PCS phones only operate in areas where PCS vendors have service up and running. Sprint Communications has a goal to offer nationwide PCS service by next year, but until then a PCS user's ability to communicate may be limited by his vendor's infrastructure.

Want to use this article? Click here for options!
© 2012 Penton Media Inc.

This month in Access Control

• Targeting The Customer
• Electronic Pedigrees
• One Hero Among Many
• Who? What? When? Where? Why?
• More from September's issue