Lesson plan
Chaocipher
The Chaocipher is a cipher method invented by John Francis Byrne in 1918 and described in his 1953 autobiographical Silent Years. He believed Chaocipher was simple, yet unbreakable. Byrne stated that the machine he used to encipher his messages could be fitted into a cigar box. He offered cash rewards for anyone who could solve it. Byrne tried unsuccessfully to interest the US Signal Corps and Navy in his system. Although numerous students of classical cryptanalysis attempted to solve the challenge messages over the years, none succeeded. For 90 years, the Chaocipher algorithm was a closely guarded secret known only to a handful of persons. In May 2010 Byrne's daughter-in-law, Patricia Byrne, donated all Chaocipher-related papers and artifacts to the National Cryptologic Museum in Ft. Meade, Maryland, USA. This led to the disclosure of the Chaocipher algorithm.
Article summary
The Chaocipher is a cipher method invented by John Francis Byrne in 1918 and described in his 1953 autobiographical Silent Years. He believed Chaocipher was simple, yet unbreakable. Byrne stated that the machine he used to encipher his messages could be fitted into a cigar box. He offered cash rewards for anyone who could solve it. Byrne tried unsuccessfully to interest the US Signal Corps and Navy in his system. Although numerous students of classical cryptanalysis attempted to solve the challenge messages over the years, none succeeded. For 90 years, the Chaocipher algorithm was a closely guarded secret known only to a handful of persons. In May 2010 Byrne's daughter-in-law, Patricia Byrne, donated all Chaocipher-related papers and artifacts to the National Cryptologic Museum in Ft. Meade, Maryland, USA. This led to the disclosure of the Chaocipher algorithm.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.