Difference between revisions of "Solved 340-character cipher"

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UPDATE: [[Compilation of news reports about the solution]]
 
UPDATE: [[Compilation of news reports about the solution]]
  
== Articles and information about the 340 cipher ==
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== Images ==
  
 
[[File:340-cipher-hi-resolution.jpg|thumb|High-resolution scan of the 340-character cipher]]
 
[[File:340-cipher-hi-resolution.jpg|thumb|High-resolution scan of the 340-character cipher]]
[[File:Sfchron340cipher.png|thumb|As it appeared in the SF Chronicle on Nov 13, 1969 (Credit: Deborah Silva, who posts as Seagull on the Zodiac forums)]]
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[[File:Sfchron340cipher.png|thumb|Cipher as it appeared in the SF Chronicle on Nov 13, 1969 (Credit: Deborah Silva, who posts as Seagull on the Zodiac forums)]]
  
*[[Encyclopedia of observations]] - A collection of observations about the cipher text
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== More Info ==
*[[Comparison of cipher alphabets]]
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*[[Comparison of character repetition rates]]
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[[Articles and details about the 340]]
*[[Comparison of sequence repetition rates]]
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[[Homophone sequences]]
*[[Levenshtein distance analysis]] - A look at the occurrences of repeated sequences that are not exact matches.
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[[The Pivots]]
*[[Quadrant analysis]] - Do the n-gram counts improve If we split the cipher text into four quadrants?
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[[Transpositions and other possible variations]]
*[[Quadrant analysis Part 2]] - An expansion of the previous quadrant analysis experiment.  Is it possible to produce quadrant arrangements that increase the number and quality of homophones detected algorithmically?
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[[Hypothesis Testing]]
*Information theory (entropy, randomness, etc)
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[[Halloween Card]]
*[[FBI analysis from Dan Olson]]
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[[Timeline of arriving at the solution]]
*[[Cipher-related excerpts from case documents]]
 
*[[Word frequency analysis]]
 

Revision as of 07:04, 8 July 2021

Zodiac, the serial killer who terrorized Northern California in the late 1960s, sent four ciphers to local newspapers. The first cipher was separated into three different parts and each part was sent to Vallejo Times-Herald, the San Francisco Chronicle, and the San Francisco Examiner. The combination of all three parts formed a 408-letter cipher, which was decrypted one week after it was received. Zodiac also sent a 340-letter cipher, mailed on a card on November 8 1969, that was recently solved.

UPDATE: Compilation of news reports about the solution

Images

High-resolution scan of the 340-character cipher
Cipher as it appeared in the SF Chronicle on Nov 13, 1969 (Credit: Deborah Silva, who posts as Seagull on the Zodiac forums)

More Info

Articles and details about the 340 Homophone sequences The Pivots Transpositions and other possible variations Hypothesis Testing Halloween Card Timeline of arriving at the solution