How’s this for the plot of a spy story:
William Friedman, often regarded as the father of American cryptography, shares a meal in 1951 with his Swiss friend Boris Hagelin. They make a “handshake agreement” where Hagelin’s company will, in exchange for certain payments, allow the CIA and the BND to essentially control the development of the company’s mechanical encryption and decryption machines. For the next 30+ years, the CIA and the BND are able to read the crypto traffic of essentially any country in the world except for the “Five Eyes” (a very private club consisting of Australia, Britain, Canada, New Zealand, and the United States), China, and the Soviet Union.
Here’s the thing: this isn’t the plot for a spy story. This is a short summary of something that actually happened. The operation’s codename was Rubicon, the company was Crypto AG, and Rubicon was quite possibly the most successful intelligence operation in history.