The Spy Who Loved My Typewriter

The year 1985 was declared by the press to be "The Year of the Spy."  That year there were a large number of high profile arrests of foreign agents including  John Anthony Walker, Richard Kelly Smyth, Sharon W. Scranage, Ronald William Pelton, Randy Miles Jeffries, Edward Lee Howard, and Jonathan Jay Pollard. (Pollard was actually just unexpectedly paroled so the topic came to mind.) These were Russian spies, Israeli spies, Chinese spies even one from Ghana. But there was another big spying story...

CBS broke the story that the U.S. Embassy in Moscow was bugged. This is no surprise to the cynical but the CIA and CBS has to indignantly pretend to be surprised. What was amazing to me was how they were spying. Yes they had the usual "audio bugs" on phones and in rooms but also inside typewriters. Correspondent David Martin reported:

"Soviet agents secretly installed tiny sensing devices in about a dozen embassy typewriters. The devices picked up the contents of documents typed by embassy secretaries and transmitted them by antennas hidden in the embassy walls. The antennas, in turn, relayed the signals to a listening post outside the embassy... Depending on the location of the bugged typewriters, the Soviets were able to receive copies of everything from routine administrative memos to highly classified documents."

In a typewriter? That sounds a bit noisy to me. But CBS was claiming that the Soviets had the technology to back engineer the contents of a document form the sounds inside a typewriter. For the record, the NSA confirmed this was true. [SOURCE] the U.S. had first tried to build an embassy in 1979 and had to quit... there were too many bugs. The apocryphal story is that they were poured right into the concrete. A new embassy was built and while the concrete may have been clean... the US seal on the wall and the IBM Selectric II and III typewriters were not: 1981 IBM Selectric III on the Typewriter Database

Over the next 100 days every electronic device at the embassy was replaced, including all 250 typewriters. The project was assigned the code name GUNMAN and it ran under COMSEC. The removed equipment was examined at Fort Meade with X-ray machines. The project manager Walter Deeley offered a bounty of $5,00 for each found bug. In the IBM Selectrics they found an extra coil on the power switch. It was a bug, A total of 16 were found. Their new project at the NSA was reverse engineering how the bug worked. More here.

Most other models of typewriter had individual metal arms for each letter that swung up to strike a ribbon against the paper to make an imprint. IBM Selectrics,were unique and used a round ball with characters around the outside surface. When a typist struck a key, the ball moved into position over an inked plastic ribbon and dropped to imprint the letter or number onto the paper. In addition to the coil the bugged units had an additional spring lug and screw and interpose latch (bail). The movement of that latch controlled the pitch and spin of the ball. This could be detected magnetically by the sensors concealed in the bar and  converted into a digital electrical signal. The signals were encoded into a four-bit frequency select word (FSW). The bug was able to store up to eight four-bit characters in a buffer. When the buffer was full, it transmitted the data. The bugs used all used burst RF transmissions at 30, 60, or 90 MHZ to send back their data. Amazing.

This kind of work really makes PRISM look ham-handed.