# Oranchak 2024: The Solution of the Zodiac Killer's 340-Character Cipher > David Oranchak, Sam Blake, Jarl Van Eycke, 2024. 38 records on Mysteries Department cite it. The main source for the whole project. Source: https://mysteriesdept.com/sources/SRC0D71P64M215H/the-solution-of-the-zodiac-killers-340-character-cipher Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) --- [Sources](https://mysteriesdept.com/sources)[Zodiac ciphers](https://mysteriesdept.com/mysteries/zodiac-ciphers)Oranchak 2024 **0** # The Solution of the Zodiac Killer's 340-Character Cipher David Oranchak, Sam Blake, Jarl Van Eycke, 2024. _arXiv:2403.17350 [cs.AI], 26 March 2024_. The solvers' 62-page account: history of all four ciphers, the Hardens' Z408 solution, fifty years of attempts on Z340, the period-19 statistics, the 2020 batch of transposition variants, the (1,2)-decimation, the corrections for row 15 and LIFE IS, the final key and plaintext, the FBI's two statements of 11 December 2020, and the status of Z13, Z32 and the Z408 tail. **Zodiac ciphers** PreprintChecked against the original0 ## What it's used for here The main source for the whole project. ## Cited by on this site 38 records [An earlier claimed solution (Graysmith, Penn and others) is correct and the 2020 reading is a coincidence.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PGMJ5JDY/an-earlier-claimed-solution-graysmith-penn-and-others-is) Answer ANS [The Oranchak, Blake and Van Eycke decryption is the message the writer enciphered.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PF5P4ZMP/the-oranchak-blake-and-van-eycke-decryption-is-the-message) Answer ANS [The tail is a second message under a different key or procedure.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PN160V6W/the-tail-is-a-second-message-under-a-different-key-or) Answer ANS [The tail is filler, copied from symbols above, to make the third section match the other two in size.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PMHJ495N/the-tail-is-filler-copied-from-symbols-above-to-make-the) Answer ANS [Z13 does not encode a name; it is a taunt or meaningless.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PJB87R91/z13-does-not-encode-a-name-it-is-a-taunt-or-meaningless) Answer ANS [Z13 uses a further step (transposition, nulls, or a key unlike Z408's), as Z340 did.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PHVM3PW3/z13-uses-a-further-step-transposition-nulls-or-a-key-unlike) Answer ANS [Z32 is a bluff and encodes nothing usable.](https://mysteriesdept.com/mysteries/zodiac-ciphers/answers/ANS0D71PKT47Q58/z32-is-a-bluff-and-encodes-nothing-usable) Answer ANS [The 20 April 1970 letter with Z13](https://mysteriesdept.com/mysteries/zodiac-ciphers/artifacts/ART0D71PQ7G6W87/the-20-april-1970-letter-with-z13) ART [The 26 June 1970 letter with Z32 and the marked map](https://mysteriesdept.com/mysteries/zodiac-ciphers/artifacts/ART0D71PQFA1NYK/the-26-june-1970-letter-with-z32-and-the-marked-map) ART [Z340 (one sheet mailed to the San Francisco Chronicle)](https://mysteriesdept.com/mysteries/zodiac-ciphers/artifacts/ART0D71PPQW7WX1/z340-one-sheet-mailed-to-the-san-francisco-chronicle) ART [Z408 (three sheets mailed to the Times-Herald, Examiner and Chronicle)](https://mysteriesdept.com/mysteries/zodiac-ciphers/artifacts/ART0D71PP887D0G/z408-three-sheets-mailed-to-the-times-herald-examiner-and) ART [A key derived from the first nine transposed rows maps all 63 symbols with no conflicts and reads the rest,…](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PFDG382N/a-key-derived-from-the-first-nine-transposed-rows-maps-all) Evidence EVD [Earlier claims used anagramming or free rearrangement; the FBI found none with merit over 51 years.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PGWC02TJ/earlier-claims-used-anagramming-or-free-rearrangement-the) Evidence EVD [Fifteen of its 18 symbols are unique there, so many readings fit and none is preferred.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PN904YQ5/fifteen-of-its-18-symbols-are-unique-there-so-many-readings) Evidence EVD [The FBI's CRRU says it independently verified the decryption (statement of 11 December 2020).](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PFNA2XSJ/the-fbis-crru-says-it-independently-verified-the-decryption) Evidence EVD [The covering letter says the code and the map give the bomb's location.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PKAG57EP/the-covering-letter-says-the-code-and-the-map-give-the-bombs) Evidence EVD [The placement of LIFE IS and the row-15 shift are the solvers' corrections, not features read directly off…](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PGCR1JAP/the-placement-of-life-is-and-the-row-15-shift-are-the) Evidence EVD [The plaintext refers to the caller on Jim Dunbar's TV programme of 22 October 1969, seventeen days before the…](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PFX41ST5/the-plaintext-refers-to-the-caller-on-jim-dunbars-tv) Evidence EVD [The symbols in the tail appear to repeat symbols from the rows above.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PMSC4RHT/the-symbols-in-the-tail-appear-to-repeat-symbols-from-the) Evidence EVD [The two solved ciphers contain boasts, not operational information.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PM1Y105K/the-two-solved-ciphers-contain-boasts-not-operational) Evidence EVD [Twenty-nine of 32 symbols are unique, so many locations fit equally well.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PKJA4MQQ/twenty-nine-of-32-symbols-are-unique-so-many-locations-fit) Evidence EVD [Z340 showed the writer added transposition and irregularities to homophonic substitution.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PJ3E3KHB/z340-showed-the-writer-added-transposition-and) Evidence EVD [Z408 explicitly refuses to give his name, and Z340 contains none.](https://mysteriesdept.com/mysteries/zodiac-ciphers/evidence/EVD0D71PJK2014E/z408-explicitly-refuses-to-give-his-name-and-z340-contains) Evidence EVD [Letter with Z32 and a marked map, claiming a bomb](https://mysteriesdept.com/mysteries/zodiac-ciphers/events/EVT0D71PCZC5X3C/letter-with-z32-and-a-marked-map-claiming-a-bomb) EVT [Oranchak, Blake and Van Eycke submit their Z340 solution to the FBI's CRRU](https://mysteriesdept.com/mysteries/zodiac-ciphers/events/EVT0D71PD766H7B/oranchak-blake-and-van-eycke-submit-their-z340-solution-to) EVT [The solvers post their full account on arXiv](https://mysteriesdept.com/mysteries/zodiac-ciphers/events/EVT0D71PDYM4D3J/the-solvers-post-their-full-account-on-arxiv) EVT [Z340 mailed to the San Francisco Chronicle](https://mysteriesdept.com/mysteries/zodiac-ciphers/events/EVT0D71PC7Y5DWX/z340-mailed-to-the-san-francisco-chronicle) EVT [Z408 mailed in three parts to the Times-Herald, the Examiner and the Chronicle](https://mysteriesdept.com/mysteries/zodiac-ciphers/events/EVT0D71PBRA3YYB/z408-mailed-in-three-parts-to-the-times-herald-the-examiner) EVT [Bettye Harden](https://mysteriesdept.com/mysteries/zodiac-ciphers/people/FIG0D71PAH85AQV/bettye-harden) FIG [David Oranchak](https://mysteriesdept.com/mysteries/zodiac-ciphers/people/FIG0D71PAS2760T/david-oranchak) FIG [Donald Harden](https://mysteriesdept.com/mysteries/zodiac-ciphers/people/FIG0D71PA9E298W/donald-harden) FIG [Jarl Van Eycke](https://mysteriesdept.com/mysteries/zodiac-ciphers/people/FIG0D71PB8P1YFT/jarl-van-eycke) FIG [The Zodiac ciphers](https://mysteriesdept.com/mysteries/zodiac-ciphers) The mystery article MYS [Federal Bureau of Investigation, Cryptanalysis and Racketeering Records Unit](https://mysteriesdept.com/mysteries/zodiac-ciphers/organisations/ORG0D71PBGG5HJG/federal-bureau-of-investigation-cryptanalysis-and) ORG [Does Z32 encode a location?](https://mysteriesdept.com/mysteries/zodiac-ciphers/questions/QST0D71PEP27A6T/does-z32-encode-a-location) Question QST [Is the 2020 decryption of Z340 the true message?](https://mysteriesdept.com/mysteries/zodiac-ciphers/questions/QST0D71PE6E3RE4/is-the-2020-decryption-of-z340-the-true-message) Question QST [What are the last 18 letters of Z408?](https://mysteriesdept.com/mysteries/zodiac-ciphers/questions/QST0D71PEXW0XFF/what-are-the-last-18-letters-of-z408) Question QST [What does Z13 say?](https://mysteriesdept.com/mysteries/zodiac-ciphers/questions/QST0D71PEE83PWE/what-does-z13-say) Question QST ## Cite it ``` Oranchak, D., Blake, S., & Van Eycke, J. (2024). The Solution of the Zodiac Killer's 340-Character Cipher. arXiv:2403.17350 [cs.AI], 26 March 2024. https://arxiv.org/abs/2403.17350 ``` [Read it free at arxiv.org](https://arxiv.org/abs/2403.17350) Key **SRC** 0D71P64M215H Kind Preprint Rights arXiv-nonexclusive Kept 27 Oct 2026, for editors Checked Against the published original Added by [apollo](https://mysteriesdept.com/u/apollo) The record Bibliographic records are CC0. Take this one as CSL-JSON, BibTeX or RIS. [CSL-JSON](https://mysteriesdept.com/sources/SRC0D71P64M215H/the-solution-of-the-zodiac-killers-340-character-cipher/csl.json)