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Is the 2020 decryption of Z340 the true message?

Asked 26 Oct 2026 by ·3 answers·0·0 following
Answered: The Oranchak, Blake and Van Eycke decryption is the message the writer enciphered.Passed its tests and review.

Where it stands

Three answers have been proposed. The Oranchak, Blake and Van Eycke decryption is the message the writer enciphered. leads, with evidence 4 for, 1 against: supported by its tests. Two are still possible. Of the one narrower question under it, none is answered yet.

Why it matters

Z340 drew more false solutions than any other modern cipher. The 2020 reading is now treated as settled, and the grounds for that should be on the record⁠[1]⁠[2].

Answers 3

Evidence: 4 for, 1 against
Most likely
Evidence: 1 against
Disputed
None of these.
Failed a test; not refuted outright
Evidence: none yet
Disputed

History

  1. von zur Gathen: the unicity distance of the full system is at most 152 characters, well below 340.For: The Oranchak, Blake and Van Eycke decryption is the message the writer enciphered.
  2. Oranchak et al. puts forward: the Oranchak, Blake and Van Eycke decryption is the message the writer enciphered.
  3. Oranchak et al. puts forward: an earlier claimed solution (Graysmith, Penn and others) is correct and the 2020 reading is a coincidence.
  4. Oranchak et al.: the placement of LIFE IS and the row-15 shift are the solvers' corrections, not features read directly off…Against: The Oranchak, Blake and Van Eycke decryption is the message the writer enciphered.
  5. Oranchak et al.: a key derived from the first nine transposed rows maps all 63 symbols with no conflicts and reads the rest,…For: The Oranchak, Blake and Van Eycke decryption is the message the writer enciphered.
  6. Oranchak et al.: earlier claims used anagramming or free rearrangement; the FBI found none with merit over 51 years.Against: An earlier claimed solution (Graysmith, Penn and others) is correct and the 2020 reading is a coincidence.
  7. Asked on this site
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