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bug The object to the right is a bug - a tiny microphone that can be hidden almost anywhere. It is but one in a startling arsenal of devices used today to spy on personal enemies, competing companies, and other world powers. Such devices played a major role in the recent spying controversy between the United States and the Soviet Union. Much was written about the resulting international skirmishing. But little has been said about the devices themselves, their incredible capabilities, and the astonishing technology on which they are based. Almost nothing has been written about how some of the most interesting equipment works.

What kinds of bugs are available? How are they put in place? Detected? Designed to avoid detection? What about tuning in on the computer down the block to learn the secrets it contains? Bugging typewriters? Bouncing laser beams against window panes?

In the larger picture, what is happening in the bugging war between the superpowers? What did security officials find in the Moscow embassy?

Most of this information is classified. Yet much can be learned. Today, snooping is big business with widespread industrial and commercial applications. Companies make and sell a remarkable variety of devices.

In addition, bits and pieces of information have leaked from Congressional hearings and from other unclassified sources. Those with inside knowledge make occasional statements that, combined with what we know about commercial equipment, can be revealing. From these sources emerges a hazy but informative picture of the shadowy world of spying.

The Veil of Secrecy

When a bug is feared or suspected, the first defense is to conduct a room sweep with devices that can detect hidden transmitters, tape recorders, and some telephone bugs. At left, Rob Muessel of Information Security Assoc. sweeps a wall with a nonlinear junction detector, a microwave-transmitting device that hunts out semiconductors. Most transmitters and tape recorders and some telephone bugs contain semiconductors, diodes or integrated circuits. An alarm tone in the operator's earphones signals a find. An added plus: The transmitter need not be transmitting to be detected. Another countermeasure is to use a radio-frequency scanner (top), which scans the airwaves as the operator looks for transmission peaks. Once the bug is located, its transmission can be monitored. The drawback to this method is that it can be thwarted by a burst-type bug.

Nobody wants to talk about bugs. The Central Intelligence Agency and National Security Agency refused to be interviewed. Private companies were also wary; several prospective sources hung up when they learned why we were calling.

Except for secret high-tech devices used by government spies, the common bug is ingenious but not terribly sophisticated. 1. A drop-in transmitter replaces the microphone in a telephone receiver. It transmits a radio signal when the phone is in use and gets its power from the telephone line. 2. Another small bug, wired into a light switch may use AC lines for both power and transmission. 3. Tiny microphones, one from a hearing aid (left) and the other an electret-type (right), can be wired into walls or slung into the space above a dropped ceiling. 4. FM transmitters were all obtained by mail or in shops; battery life: one day. 5. Ordinary item, an intercom, and outlet, are disguised transmitting devices.

The Soviets allege that bugs, including a transmitter wired into a brick from the Soviet embassy in Washington, D.C. (left), and a microphone and transmitter fitted into a socket for the master TV antenna from the residence of their U.N. representative (right, were planted by U.S. spies.

Most manufacturers of bugs make it clear that they will not talk for publication. For example, Intelligence Devices Corp. of Fairfield, N.J., advertises 100 different pieces of security equipment. The ad begins, "We supply the most sophisticated electronic intelligence devices available to law enforcement, but law prohibits us from discussing our products in detail without the proper written requests...Complete and detailed product information is available only to authorized agencies upon written request on departmental letterhead."

    Despite such problems, we were able to dig out some surprising facts. Among them:
  • Bugs can be made almost any size. The smallest we actually saw was the one picture to the right. It is a tiny electret microphone just 3/16-inch across at its largest dimension. The security expert who gave it to us wouldn't say where he got it.
  • Bugs are widely available. Tiny ones undoubtedly used in industrial espionage can be bought openly in some European and Asian cities, though they're illegal there as here. Easily available even here, however, are wireless microphones smaller than a cigarette pack. They have legitimate uses, but also can be used for bugging.
  • Bugging experts use dozens of methods to keep their devices from being detected, from planting them in electronic equipment to wiring them with the latest in fiberoptic technology. The Soviets planted thousands of false bugs in the now infamous US embassy in Moscow to confuse sweeping attempts.
  • While the CIA and FBI undoubtedly bring the latest in electronics technology to bear in acquiring super-small, difficult-to-detect devices, surprisingly sophisticated bugs are relatively easy to build. We obtained plans for the so-called "martini olive" bug that received considerable publicity several years ago. It can be built in any reasonably equipped electronics workshop by anybody with even a moderate amount of electronics knowledge.
  • Sensitive information in computers is easy to steal; a $500 device can tune in on any unprotected computer at ranges of perhaps a mile and reproduce anything appearing on the computer's screen. A British expert recently gave a demonstration that left computer users in a state of shock.
  • The highly publicized laser beam that can be bounced off a window pane to eavesdrop on voices inside sounds flashy, but is apparently of limited usefulness in real life.
  • People who don't want their conversations bugged rely on frequent sweeping of sensitive areas. We saw a demonstration of several kinds of advanced equipment used in this effort.

Because of the sensitive nature of the subject, no one was willing to come right out and talk in detail about bugs and bugging, or even to admit to having detailed knowledge. Nevertheless, we uncovered bits and pieces and a picture began to form. Bugs - devices designed to eavesdrop surreptitiously on conversations - we learned, come in three basic forms. First are units that contain both a microphone and a small transmitter. They are hidden in a room and transmit a signal to a nearby receiver. If such a unit is tied into a power source - room electrical wiring or a telephone line, for example - it can transmit indefinitely. And the wiring may also be used to route signals from the bug to distant points.

Second are microphones. Because they can be extremely small, they can be hidden almost anywhere. But they require wires - which can be smaller than a human hair - to conduct the signal to a listening post outside the room. Finally, there are passive devices, which sit silent and unobserved but which can transmit room sounds when stimulated by a radio signal from outside. More about this later.

Although all bugs fall into one of these categories, they come in a variety of shapes, forms, and sizes. Private investigators who talked on the condition they not be identified told us that bugs they find are sometime built on small circuit boards, at other times they're simply strung together in little balls of wires and components that look like a tangle of spaghetti. They can be put in small cases or encapsulated in epoxy. Epoxy encapsulation is attractive, says a textbook we saw, because such bugs look like little blobs of unidentifiable substances and may not even be recognized as bugs. Incidentally, the book, Measure by Countermeasure, a Textbook on Anti-Eavesdropping, was written to train security professionals who attend the school conducted by a security company called Microlab/FXR located in Livingston, N.J. It talks about bugs, now they work, their sizes and types, and how to find and recognize them.

While some bugs are homemade, others are available commercially; you can buy them from radio supply stores where they are sold as wireless microphones or baby-sitting devices. Several such devices are pictured in this article. They cost just a few dollars and transmit a signal that can be picked up by an ordinary FM radio. "Lots of people are taking Radio Shack wireless microphones and converting them," says Charles Miller, a technician with Law Enforcement Associates, Inc., of Medford, N.J. "Take the shell off, and if you're good with your hands you can make them pretty small." "You can find them advertised in the backs of magazines," says Rob Muessel, a technical service coordinator for Information Security Associates of Stamford, Conn.

More sophisticated devices - legally available in this country only to law-enforcement officers - are available off the shelf in Tokyo, Hong Kong, and at the Frankfurt airport in West Germany. "In Japan they make on transmitter that's a quarter inch square and about one and one-half inches long," says Muessel.

Cover Bug - Tiny components inside a 0.2 by 0.2 by 0.9 inch electret microphone ensure small size but high sensitivity. The electret diaphragm (see text) is sandwiched between conducting metal electrodes, connected to a translator. As the electret flexes, it generates a current that is amplified by the transistor. External leads supply transistor power and a path to other circuits.

Bugs can be very small - small enough to be built into a fountain pen or stuck into a small hole in the wall, the binding of a book, or elsewhere. Harry A. Augenblick, president of Microlab/FXR, tells of one clever design. "This is a picture-hook bug," says Augenblick, pointing to a one-inch-long, 1/4-inch-diameter spike with a picture hook on its flat end. "First you use a tool that punches a hole in a wall, then you slip the bug in. After you hang the picture back on the wall, you wouldn't know for years that somebody had changed your picture hook."

Another investigator who insisted on anonymity showed us a transmitter about the size of a book of matches. "With its battery pack this one will transmit for nine days," he said. "You can throw one of these guys in a trash can and retrieve it later." How far can such bugs transmit? "A matchbook-sized device can have a range of a quarter of a mile," says Frank G. Mason, president of a Fairfield, Conn., security firm that bears his name.

The variety is endless. Pictures accompanying this article show a bug that slips into a telephone handset. Picking up the handset supplies telephone line voltage to the bug, which then transmits anything said into the mouthpiece to a nearby receiver. "We once got a call from a guy who said every time he picked up his telephone his television picture went blurry," said Muessel. "We never found out what that meant because he didn't hire us. But there was probably a transmitter planted inside his phone."

Similar bugs can be designed to send out signals all the time - even when the telephone is thought to be inoperative. "Wires are often put in telephones for nonexistent intercoms or speaker phones," says Mason. "So there is a spare pair of wires." If someone intent on bugging can get to a terminal board in that building, he can wire the spare pair so that the microphone in the telephone sends a voice signal to the terminal even when it is on the hook. "In government agencies where the phones must be replaced quite often," he says, "they test phones before new ones are put in and find that eight out of ten phones are 'hot on the hook'."

Another astonishing fact is how easy it is to build very small - and very effective - bugs. For example, a San Francisco security expert name Hal Lipset won momentary fame some years ago as the man who had bugged a martini olive. During our research we obtained plans and directions on how to build the infamous martini-olive bug.

The plans call for hollowing out opposite ends of a small copper cylinder with a lathe, then carefully mounting in the two cavities about a dozen tiny parts - transistors, resistors, capacitors - available from any electronics supply house. The instructions describe how to cut apart a standard alkaline battery and use parts of it to construct a very small battery. Finally, a disc made of foil serves as a microphone. The instructions say the unit can be made in several sizes, including one in which the finished device is approximately 1/2 inch in length and slightly less than that in diameter. It will transmit at a frequency of 600 megahertz.

How do you make it look like an olive? "A case may be formed around the unit with fiberglass putty and molded to any desired shape," the instructions conclude. The antenna is disguised as a toothpick in the olive!

The most interesting bug we saw was the one pictured on the cover, which falls into the second category: microphones. The bug, a miniature electret microphone, would need thin wires leading to a receiving station. That would be no problem for someone with access to the target room; we were told that the "wires" can actually be two lines of metallic paint on a wall, which are then covered by regular paint. Such an installation is almost impossible to find.

Although the term electret, representing an electrostatic analogy with permanent magnets, first appeared in 1885, a practical device wasn't devised until 1925 (the drawing shows its operating principle). An electret is made by polarizing certain waxes or plastics with high voltage; one side has a strong positive charge; the opposite side of the electret material has an equally strong negative charge. An electrical potential is permanently "frozen" into the material. Practical applications of electrets for microphones became possible with the development of low-noise transistors and suitable dielectric - nonconductive - materials.

Just how small bugs can be is unknown. Frequently news reports speak of "pinhead-sized" bugs. Yet there is no evidence that bugs that small really exist. It seems at least possible that they do not, and that the pinhead estimate is a result of logical confusion. The electret mike contains a tube on one side through which the sound enters. The hole is approximately the size of a pinhead. Thus it is possible that the smallest bugs are not themselves pinhead sized, but require a pinhead-sized hole in the wall through which they pick up sound. Says Mike Russell of Sherwood Communications in Southampton, Pa., "Microphones are usually found in ceilings or mid-level in the wall. They're usually behind the wall, with a tiny hole the size of a pencil point drilled through."

Perhaps the most sneaky of all bugs is the passive device. It first came to light some years ago when American security experts revealed that they were worried about low-level microwaves beamed by the Soviets at the American embassy in Moscow. Now they're reasonably sure that these were aimed at mysterious cavities built into the structures of the buildings.

Steel reinforcing rods or small cone-shaped metal cavities can be hidden in the walls during construction. Sound waves within the room cause the walls to vibrate slightly, distorting these metal structures. If a microwave beam at a critical frequency is aimed at such a device, the reflected signal is slightly modulated by the sound vibrations. Careful analysis of the returning reflections can re-create the original voice signals that caused the vibration.

Perhaps the most advanced - and talked about - technique of all is bouncing a laser beam off a window. The window pane vibrates slightly from the sound pressure generated by the conversation inside. The returning laser beam is modulated by these vibrations, and the original voice signals are recovered.

One of the textbooks designed to train security personal contains a section on such devices. It says one can be built using a General Electric H1A1 laser, which radiates about 35 watts of power in the infrared band. It is pulsed with a simple transistor circuit at 10 kilohertz. The receiver is an astronomical reflecting telescope bought from Edmund Scientific Company. A photomultiplier tube, which turns the pulsed infrared signal into a series of electrical pulses, is mounted in place of the eyepiece. The output of the photomultiplier is then fed to an amplifier to recover the voice signal from within the room.

It is questionable just how effective this technique is. Richard Heffernan, vice president of Information Security Associates says the technique probably doesn't work too well. He points out that the window pane also vibrates from passing traffic and random noise, and picking out the relatively low-level voice signals would be difficult. Other experts point out that filtering techniques have been developed to get clear pictures out of TV signals returning from space - signals that when they were received are buried in and obscured by noise. Such processing might dig voices out of the background noise.

Cleaning Up the Premises

While companies are reluctant to talk about bugging, they're often happy to talk about their anti-bugging activities, which are legal, and which, indirectly, reveal a good bit about bugs, too. For example, Microlab/FXR's Augenblick gave Associate Editor Naomi Freundlich a demonstration of the company's SuperScout - a $25,000 bug detector the company says is used daily by 53 lesser world governments and hundreds of Fortune 500 companies.

High-tech bugging techniques - and a costly fix

1. MICROWAVE INTERCEPTS. Microwave dishes used by telecommunication firms relay voice and computer signals from point to point or back and forth to communication satellites. Although the dishes concentrate the beams into narrow paths, signals that spill over can easily be intercepted at many points along the beam path. 2. PASSIVE BUGS. In 1952, an unusual type of bug, a small metal cylinder, was found in a decoration at the U.S. embassy in Moscow. This cylinder contained no electronics and had no source of power, but it apparently relayed voices in the room to a Soviet listening post outside the embassy. By beaming 330-MHz radio waves at the cylinder from outside the embassy, the Russians picked up return signals modulated by voices in the room, which vibrated part of the tiny metallic can. 3. LASER AUDIO SURVEILLANCE. Because laser beams don't scatter and spread like ordinary light, a laser can be focused on a window some distance away. Voices in a room vibrating the window glass shift the wavelengths of the reflected beam. A receiver in the path of the refection can amplify the beam, a demodulator can separate audio from light. A laser surveillance technique that avoids most extraneous window vibrations, and avoids the difficult positioning of a laser transmitter and receiver at different locations, bounces the beam from objects within a room. Tiny flexible reflectors, planted ahead of time, can pick up voices and modulate a beam reflected to a receiver next to the transmitter. 4. BURST TRANSMISSIONS. Advanced microcircuits now enable devices smaller than a calculator to electronically encode, compress, and record information. The recording - voices or computer data, for example - can then be transmitted in a burst lasting only a split second. Such transmissions are very hard to detect on radio frequencies. 5. COMPUTER INTERCEPTS. Computers emit radio frequencies that may be intercepted some distance away. Decoding gear (see text) can then show what appears on the computer screen. 6. FALSE BUGS. Nonlinear junction detectors look much like ordinary metal detectors, except they beam radio waves into walls and pick up return signals produced when the junctions of dissimilar materials such as semiconductors radiate harmonic frequencies back to the detector.

Well-designed bugs have shielding that minimizes penetration of the detector beam and greatly reduces the harmonic frequencies reaching the detector. In Moscow, the Russians have reportedly sown the new embassy walls with "junk" junctions, complicating sweeps for true bugs. 7. SHIELDED ROOM. a cure for high-tech bugging is a specially designed room isolated from outside prying. In addition to shielding that stops radio-frequency leaks, acoustic baffles can absorb voices; ventilations and pluming must also be protected. An elaborate suspension system may "float" the entire structure. Such an add-on room has been proposed as a partial fix for the heavily bugged new embassy building in Moscow.

"It looks like a cross between a vacuum cleaner and a beach-variety metal detector," she reports. "The body of the device is a briefcase-sized receiver, and attached by long electrical cords is an adjustable boom with a flat vacuum cleaner-like head on its end that functions as an antenna. Augenblick slung it over his shoulder.

" 'We will find your little tape recorder whether it's on or off or even if you take the batteries out of it,' he promised. Moments before, out of his presence, I had hidden it on the lower shelf of the office coffee table under a stack of magazines.

"He switched on the detection device, a nonlinear junction detector. Augenblick had explained the operating principle earlier. 'Normally if I sent a signal out around this room, it would bounce off everything and the signals coming back would all have the same frequency as the one that went out,' he said. 'But semiconductors such as transistors and diodes are nonlinear devices in which current flows more readily in one direction than in the other. That means that when SuperScout transmits at exactly one gigahertz, any semiconductor nearby will generate harmonics - that is, it will send back signals in exact multiples of the original frequency - one, two, and three gigahertz, for example.'

"He methodically swept the head of the antenna up and down the office walls, across book shelves, over furniture, and finally across the floor - all the while keeping an eye on the needle at the top of the shoulder-slung portion of the device.

"Then he began sweeping over the coffee table. The monitor needle swung to the right and he grinned. 'There it is!' he exclaimed triumphantly.

"Nonlinear junction detectors can be misled - especially if electronic equipment containing semiconductors is anywhere nearby. 'In the beginning we did some very crude things,' said Augenblick. 'An operator conducting a sweep of former Israeli Prime Minister Golda Meir's office literally tore down her office wall and found nothing. There was just a simple radio in the next room.' "

Although a nonlinear junction detector such as the one Augenblick demonstrated can find just about any bug containing semiconductors if used with sufficient care, it is expensive and tedious to use. Thus many persons debugging a site use a device called a scanner, which detects RF signals from bugs instead of the circuits inside the bug. Naomi Freundlich saw one in action at Information Security Associates in Connecticut. She reports:

"Rob Muessel turned a knob on the VCR-sized receiver; at each click he homed in on radio-frequency signals. 'This instrument can scan signals from twenty kilohertz to a thousand megahertz - one gigahertz - and up into the seven- to eight-gigahertz microwave range,' he said. At one point the scanner screen danced with a whole mountain range of blue peaks, stronger than any we had seen yet. 'What are you picking up now?' I asked excitedly, imagining us picking up secret transmitted conversations. Muessel turned some dials and a particularly large peak appeared on the screen. But instead of satisfying my voyeuristic tendencies, strains of Simon and Garfunkel's song 'The Boxer' came through. We had stumbled across the FM mountain range.

" 'That's all that's really involved in using this device,' said Muessel. 'You just tune through and listen.' Tuning through and zeroing in on some of the larger peaks, we picked up ham radio, cellular telephones, and even the repetitive staccato sound of transmitted data from pocket pagers.

"Then Muessel set up a transmitter in the room. Even when there was no sound in the room there was a peak on the scanner screen. 'We sometimes use a steady sound source,' said Muessel as he turned on a high-pitched beeper. As the transmitter signal pulsed like a heart beat in time with the beeper I heard the regular sound in my earphones. I also listened as we picked up the same pulsating peak at exactly two and four times the frequency of the original.

"The RF scanner can also be used to detect hidden video cameras. 'If we had a closed-circuit TV monitor, we could hook up a television receiver and display video signals.' said Muessel as we passed a large peak from a nearby TV station."

As this demonstration illustrates, bugs that transmit continuously have a serious weakness. They're relatively easy to detect. Several ingenious schemes have been developed to minimize that possibility. For example, bugs can be built to collect information and transmit it in practically undetectable short bursts. One source speculates that such a bug could collect information in digital form for perhaps 15 seconds, then send out the whole package in one microsecond. Such a device would be practically impossible to find with a scanner.

Others come with voice-actuated circuits that turn them on when there are sounds of voices in the room, off when not. Some have remote switches by which they can be turned on and off. "I can put a bug someplace and turn it on and off remotely." Miller says. "I hear you come into the room, and if I have any idea that you're going to start checking for bugs, click, it's off." All these methods help prevent detection by scanners that look for signals being radiated.

Yet other bugs use a technique known as "snuggling" to avoid detection. The designer has it transmit at a frequency just barely different from a local TV station's, for example. Because its signal tends to be lost in the much more powerful TV signal, it may go undetected. Other bugs are frequency switchers. They transmit at one frequency for a few thousandths of a second, then change to another, and the another.

Active bugs can often be detected by nonlinear junction detectors or scanners. These methods, however, will notdetect microphones, which neither contain semiconductors nor put out an RF signal. "You can find them" says Frank Mason, "by x-raying the walls inch by inch, but that's time-consuming, expensive, and hazardous to your health. The only other defense is physical inspection such as looking for pinholes in walls"

An even more difficult-to-detect setup can be created by using a hairlike optical fiber to transmit the signal out of the room and perhaps out of the building. Because the signal is in the form of light, it creates no electromagnetic signal that can be detected, nor is it detectable by normal sweeping methods.

Bugs of many types - both transmitters and microphones - are widely used, and, according to the Microlab textbook, easily placed. The book says that Microlab never identifies its clients, what it did for them, or what it found. However, it says, the company knows of actual cases of bugging detected by others. In one case, it says, one company wanted to find out what progress a competitor was making in research. So while a member of the bugging company visited the office of the director of research at the rival company, he noted the title of a book in the office. He then bought an identical book and had it fitted with a 520-kilohertz bug. The bug, made into a thin strip and sealed in epoxy, was glued into the binding of the book. Then a maintenance worker was persuaded to substitute the bugged book for the original one. The sneaky competitors parked in a car nearby and tuned in on conversations in the research director's office.

In another case a financial operator widely known for sending flowers to his friends and acquaintances sent a bouquet to a legal firm reviewing a company's financial disclosure statement. In the flowers he planted a small commercially available wireless transmitter, tuned in to the conversations, and was able to make a profitable investment prior to the release of the financial statement.

Sometimes planting a bug turns out to be a really inside job. In February 1982 the manager of the Soviet airline in Indonesia was arrested for running a spy ring. While he was in custody, authorities became suspicious about a scar on his chest, which he said was from an operation. But a closer look showed that a bug had been planted in the man's chest so KGB agents nearby could hear all conversation around him.

Computer Bugging

Bugs have got most of the headlines in recent months, but sleuths use a lot of other high-tech tricks. One active area: eavesdropping on the sensitive information in somebody else's computer. Computer users were recently shocked to learn that it isn't even necessary for someone to have access to their premises. He can tune in to a computer from down the street. it isn't even difficult or expensive.

This fact became painfully obvious about a year ago at a computer show in Olympia, England. Representatives of major computer manufacturers were there to show off their latest products. There was much emphasis on computer security. Many models featured locks and password entries to protect against unauthorized tampering and there were encryption programs that rendered stored information intelligible to only the authorized user.

Into this scene the British Broadcasting Corporation sent a reporter and a British electronics engineer named Sean Walker. They entered the show with Walker wheeling a cart. On the cart was a video display screen, a CB antenna, a VHF receiver, and a signal processor. The entire scene was videotaped for a program that later appeared on the BBC.

As Walker strolled slowly through the show, he adjusted several dials. Soon a replica of data appearing on the screen of a nearby Epson PC AX appeared on Walker's screen simultaneously. "Any hobbyist or amateur radio enthusiast could probably put this system together in a few evenings," he said on the broadcast. The cost: about $500.

This theatrical - but sobering - stunt was based on the work of a Dutch researcher named Wim van Eck of Dr. Neher Laboratories PPT, in Leidschendam, Netherlands. It had been known for years that computers radiate weak signals theoretically capable of being decoded, but it had been widely assumed that complicated and expensive equipment - available only to government spooks - was needed to capture and make sense of these emanations.

That dream was abruptly ended when van Eck assembled readily available electronic equipment, parked a van outside of an office building, and read off information appearing on computer screens several stories up. With slightly more sensitive equipment, he says, he can pick off data from computers two kilometers away.

The principles van Eck used are well known. The words, numbers, and even graphic images appearing on a computer screen are formed by a beam sweeping across the screen in a TV-like raster. The beam is off where the screen is supposed to be dark, and on as it crosses an area that is supposed to light up. This switching of the beam on and off generates a digital signal that can be picked up some distance away, as van Eck demonstrated. If another display unit at the receiving location has a beam sweeping across it in perfect synchronization with the one at the computer being tapped, and if the received signal is used to switch on the electron beam in this display, then a display identical to the one at the original computer will be formed. Van Eck pointed out that the signal is easy to pick up, because the signal that switches the beam on and off is amplified to several hundred volts, unlike other signals in the computer or display. Thus it radiates strongly.

The only real trick is synchronizing the beam sweeping back and forth across the eavesdropping display with the one on the computer being bugged. A television broadcast contains synchronization signals that are used by the receiver to keep its beam in sync with the beam at the originating station. A computer transmits no such sync signal. So van Eck built a special circuit to discover the original sync mode and generate a new signal to synchronize the receiver. Then he presented a scientific paper on the device at an industry meeting. Securicom '85, in Cannes, France, in 1985.

Computers involved in national security - especially those in such places as embassies in foreign countries - are presumably shielded to prevent such eavesdropping. For 20 years the U.S. Government has had a series of standards called TEMPEST designed to cut down on the radiation allowed to escape from a computer. (TEMPEST was originally an acronym for Transient Electromagnetic Pulse Emanation Standard.) Although no one will comment officially, we learned informally that the standards require that the potential signal be attenuated by about 70 dB - a large amount. But one source estimates that it may double the cost of a computer to build in this kind of protection. A spokesman for Wang Laboratories Inc., which builds TEMPEST-protected computers, said it adds 20 to 50 percent to the cost.

TEMPEST-protected computers are probably reasonably secure. But defense officials worry that bits and pieces of sensitive information on small computers in engineering development departments, in the offices of government officials, and elsewhere may not be so secure. And banks, insurance companies, hospitals, and others with confidential information are probably vulnerable.

A low-cost protection system may be the solution for these units. Al Montross, president of Dataprotek in Boca Raton, Fla., builds a shielded cover that goes over the entire computer. Montross says it cuts down on the radiated signal - by 60-65 dB rather than TEMPEST's reported 70 - and costs only $650.

Low-Tech Bugging

Bugging unprotected computers is relatively easy because it does not require access to the premises. But even typewriters can be bugged with a little effort. For example, in March 1985 U.S. officials announced angrily that the Russians had planted a large number of bugged typewriters in the U.S. embassy. Apparently they had either planted bugs in the IBM Selectrics during their shipment to the embassy or had exchanged them for pre-bugged models. How do you bug a typewriter? To find out, Senior Editor John Free visited Ace Typewriter Sales & Repair Company's shop in New York. He reports:

"I climbed the flight of stairs and met Paul Federman, manager of the shop. IBM Selectrics are totally mechanical, he explained, except for a drive motor to slide the type ball back and forth horizontally. A complex system of levers, gears, and other elements spins and tilts the type ball correctly to print the letter you strike. This mechanical motion, however, is quite simple to transform into an electrical signal that can be transmitted out of the building and used to recreate anything typed on the machine.

"Federman had a partially dismantled Remington typewriter sitting on the bench. Its operating principle, I learned, was similar to the Selectric's, and the same technique could be used to bug both.

"'We discovered a good way to bug the typewriters,' Federman said, attaching a cookie-sized rubber wheel to the side of the machine. Turning the wheel enabled him to slowly cycle through one keystroke. He pressed a key, then turned the rubber wheel slowly. He pointed to a thin metal strip just below the keys. Six narrow bars from deep inside the typewriter protrude through small holes in the strip. Pressing any key on the keyboard causes the six bars to assume a particular configuration peculiar to that key alone. For example, press an 'm,' and two of the bars might be stationary while four others would protrude 1/4 inch from the strip. Put six sensors - simple microswitches would do - where the bars come out of the strip, and transmit this information to the receiver nearby. By simply reading the combination of ups and downs, you can tell which key has been struck and thereby re-create the message.

"Microswitches would be pretty easy to spot, of course, but a skilled electrical technician could embed tiny magnetic or other advanced motion sensors deep within the machine where they would be highly difficult to spot. Electrical power would be no problem; the bug could be wired into the typewriter's electrical supply."

The Cold (Bugging) War

These and many other kinds of bugging devices were obviously used in the new U.S. embassy in Moscow. But it's been hard to tell what; in their outrage U.S. officials shed a lot of heat but little light over exactly what they had discovered. They charged that the entire building might have to be demolished, so packed is it with spy devices that they can probably never all be found and destroyed. Yet putting together the background information, it's possible to deduce what must have happened.

According to news reports, bugging is such a fact of life that U.S. officials simply weren't too concerned about it. They counted, the reports said, on sweeping the premises after they took over the building to get rid of the bugs. "Our assumption was that we could rectify whatever the Soviets had done once we took control of the building," said a senior State Department official. "That may have been too optimistic."

Official statements make it clear that sweeping teams found huge numbers of bugs, microphones, and other suspicious devices. They were stunned by the complexity of the bugging. What could the Soviets have put in the building that could have produced such a reaction? Practically everything: There were cables apparently connected to nothing, and reinforcing rods arranged in peculiar ways, possibly to form antennas. There were cavities of wire mesh, and small empty metal cones. All of these may well be passive units queried by microwave.

An elaborate network apparently covered the most sensitive area of the chancellery, a windowless floor obviously intended for secret operations. Hundreds of tiny microphones were apparently cleverly hidden everywhere. "Normally they could spot the wires leading to microphones," says Microlab/FXR's Augenblick. "But what the Russians appear to have done is to put the wires inside steel reinforcing bars and other metallic objects that x-rays don't penetrate."

That wasn't the end. Charles Taylor, an expert on counter-surveillance, says on thing the Russians probably did that threw such consternation into the U.S. security forces was to bury thousands of tiny diodes in the concrete used for the building. Such diodes, which could be pinhead sized and cheap in addition, could be mixed in the concrete by the thousands or even tens of thousands. Then a sweep with a nonlinear junction detector would get back thousands of signals from every place - completely masking the real bugs that undoubtedly lay hidden behind this electronic camouflage.

"It's hard to understand how we could have put ourselves at a tactical disadvantage like this," said a White House staffer. "It's a bugger's dream," Hal Lipset, the "martini olive" bug maker. "The whole building is nothing but an eight-story microphone," echoed a statement subsequently reported to have been made by Lipset, Rep. Dick Armey (R-Texas), and Rep. Connie Mack (R-Fla.).

The future of the embassy? One security man said we'd have to "destructively search" the building to find all the bugs. That's a euphemistic way of saying we'd have to tear it apart brick by brick.

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