The CIA was the secret owner of a company that made encryption devices and communication lines for spy agencies around the world—then sat back and listened while they unwittingly revealed their secrets. The revelation, described in a CIA report as “the intelligence coup of the century,” has been reported for the first time in a joint investigation from The Washington Post and German broadcaster ZDF. The company, Crypto AG, was the dominant maker of encryption devices from the Second World War until well into the 21st century. It was also a secret joint partnership between the CIA and West German intelligence that was known under the code names of “Thesaurus” and “Rubicon.” A CIA report said: “Foreign governments were paying good money to the U.S. and West Germany for the privilege of having their most secret communications read by at least two (and possibly as many as five or six) foreign countries.” The German spy agency, the BND, left the operation in the early 1990s because of fear of exposure, but the CIA didn’t sell off the company’s assets until 2018, according to the report.