I did a whole bunch of HN searches and couldn't find a previous submission. I did find a few people mentioning it in comments to other stories. Perhaps you're t

I did a whole bunch of HN searches and couldn't find a previous submission. I did find a few people mentioning it in comments to other stories. Perhaps you're thinking of the similar incident in which the Soviets bugged the American embassy’s typewriters[1]? By the way, the earliest original reporting of the story I found is from Popular Science[2], Jan. 1997, "Spies in the Xerox Machine", page 70. (The Popular Science article has the same bogus patent number I mentioned in another comment.) [1] https://news.ycombinator.com/item?id=21998774 https://news.ycombinator.com/item?id=21998774 [2] https://books.google.ca/books?id=KIEIX2X-na8C&pg=PA70 https://books.google.ca/books?id=KIEIX2X-na8C&pg=PA70