(Roughly) Daily

But sometimes it takes lots of ingenuity… and often, a great deal of time…

The United States National Security Agency—the country’s premier signals intelligence organization—recently declassified a Cold War-era document about code-breaking.

The 1977 book, written by cryptologist Lambros Callimahos, is the last in a trilogy called Military Cryptanalytics. It’s significant in the history of cryptography, as it explains how to break all types of codes, including military codes, or puzzles—which are created solely for the purpose of a challenge.

The first two parts of the trilogy were published publicly in the 1980s and covered solving well-known types of classical cipher. But in 1992, the US Justice Department claimed releasing the third book could harm national security by revealing the NSA’s “code-breaking prowess“. It was finally released in December last year. 

A key part of Callimahos’s book is a chapter titled Principles of Cryptodiagnosis, which describes a systematic three-step approach to solving a message encrypted using an unknown method… 

See how those three steps work at “Declassified Cold War code-breaking manual has lessons for solving ‘impossible’ puzzles.”

* Edgar Allan Poe

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As we ponder puzzles, we might send intelligent birthday greetings to Alfred Binet; he was born on this date in 1857. A psychologist, he invented the first practical IQ test, the Binet–Simon test (in response to a request from the French Ministry of Education to devise a method to identify students needing remedial help).

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