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What is K5 and will it be released?

Asked 26 Oct 2026 by ·Part of Is K4 solved, known but withheld, or open?·3 answers·0·0 following
Three answers, none aheadNone is ahead yet. See what would settle it.

Where it stands

Three answers have been proposed. None is ahead on the evidence yet. Three are still possible.

Why it matters

Sanborn describes K5 as a 97-character text made with the same system as K4, sharing some coded words in the same positions; Paradigm says it holds the ciphertext and will release it⁠[1]⁠[2]. A second text under the same key would make the method far easier to recover.

Answers 3

Evidence: 1 for
Still possible
Evidence: 1 for
Still possible
None of these.
Not tested enough to call either way
Evidence: none yet
Still possible

History

  1. Vergano puts forward: k5 is enciphered with K4's method and key, so its release will make K4's method recoverable by comparison.
  2. RR Auction puts forward: k5 uses a different key or method and adds little to K4.
  3. Vergano: sanborn says K4 and K5 share some coded words in the same positions.For: K5 is enciphered with K4's method and key, so its release will make K4's method recoverable by comparison.
  4. RR Auction: the auction listed K5 as a 1988 'alternate K4 plain text and coding chart', which could mean a separate chart.For: K5 uses a different key or method and adds little to K4.
  5. Asked on this site
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