# At herbal-section length the period cipher's key can't be recovered once sign boundaries must be learned > With sign boundaries learned, no solver tried recovers a planted key of the fitted period-cipher setting at Herbal A's length well enough to pass the… Source: https://mysteriesdept.com/mysteries/voynich-manuscript/evidence/EVD0DCHSNDZS8PF/at-herbal-section-length-the-period-ciphers-key-cant-be Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) --- [Voynich Manuscript](https://mysteriesdept.com/mysteries/voynich-manuscript)Evidence Evidence · Voynich Manuscript # At herbal-section length the period cipher's key can't be recovered once sign boundaries must be learned With sign boundaries learned, no solver tried recovers a planted key of the fitted period-cipher setting at Herbal A's length well enough to pass the control: lattice EM reaches 36 % of the key, and even the true key decodes below the coverage bar (0.441 vs 0.488). Only the simplest member (one sign per letter, no nulls) is partly read (key 70 %, coverage 0.407 vs 0.483), so the hypothesis remains untested on the manuscript at its fitted settings. Supported0 ## What it means Key question[How was the text produced on the page?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST08JG6BH02GE7/how-was-the-text-produced-on-the-page) Most likely: the line is a unit of the system **Most likely** unchanged Part of it[What procedure reproduces its statistics?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST08JG6T5R6RRQ/what-procedure-reproduces-its-statistics) Most likely: each scribe ran the procedure in his own way **Most likely** unchanged Part of it[Which combination of fifteenth-century cipher practices, if any, reproduces a single section's statistics on its held-out pages?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST0DCAYTD6HZV9/which-combination-of-fifteenth-century-cipher-practices-if) No answer ahead yet **Open** unchanged Answer this evidence bears on[Latin as a re-spaced homophonic stream (period practices)](https://mysteriesdept.com/mysteries/voynich-manuscript/answers/ANS0DCBFK8KPD81/latin-as-a-re-spaced-homophonic-stream-period-practices) Bears on1 for, none against **Still possible** unchanged ## Next steps 5 1 Give the T39 signs a word-internal grammar (slot-position sign tables learned from the training pages) and refit: the remaining misses (glyph predictability, one-off words, edge dependency) all say the manuscript's words are more rigidly built than freely joined signs. ~6 h [On: Which combination of fifteenth-century cipher practices, if any, reproduces a single section's statistics on its held-out pages?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST0DCAYTD6HZV9/which-combination-of-fifteenth-century-cipher-practices-if) **—** not judged 2 Homophone rung (R2 of T44): the search now sits 64 nats from the true key yet 30 % of sign uses are wrong and coverage is flat at 0.47 (bar 0.487). Before more search, diagnose which element pairs the wrong rows confuse (confusion matrix of the best state against the planted key) and whether a richer Latin model (4-gram, or word-level dictionary scoring inside EM) separates them; then rerun R2 with the same effort and the trigram-objective hopping started earlier. ~6 h [On: Which combination of fifteenth-century cipher practices, if any, reproduces a single section's statistics on its held-out pages?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST0DCAYTD6HZV9/which-combination-of-fifteenth-century-cipher-practices-if) **—** not judged 3 Segmentation-aware solver for the stream family: a segmental hidden Markov model (signs of one to three glyphs as emissions, the sticky homophone column as a latent state) fitted jointly with the key, validated on rung B of M-T40 before any use on the manuscript. ~16 h [On: Which combination of fifteenth-century cipher practices, if any, reproduces a single section's statistics on its held-out pages?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST0DCAYTD6HZV9/which-combination-of-fifteenth-century-cipher-practices-if) **—** not judged 4 Sharper null for decodes: run the fitted generator on shuffled Latin words, which keeps the cipher's structure (edge dependency, line layer) and removes plaintext order; a reading must beat that, not only the shuffled manuscript. ~3 h [On: Which combination of fifteenth-century cipher practices, if any, reproduces a single section's statistics on its held-out pages?](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST0DCAYTD6HZV9/which-combination-of-fifteenth-century-cipher-practices-if) **—** not judged Ranked by how likely each is to move the key question, for the time it takes[All 5 on the question](https://mysteriesdept.com/mysteries/voynich-manuscript/questions/QST0DCAYTD6HZV9/which-combination-of-fifteenth-century-cipher-practices-if#next) ## Sources 3 [Decipherment with a Million Random Restarts](https://mysteriesdept.com/sources/SRC0D8MQ4S22G4V/decipherment-with-a-million-random-restarts) B 2013 SRC [Segmenting Numerical Substitution Ciphers](https://mysteriesdept.com/sources/SRC08JJDRP052CH/segmenting-numerical-substitution-ciphers) A 2022 SRC [Unsupervised Analysis for Decipherment Problems](https://mysteriesdept.com/sources/SRC0DCEXM6FBS17/unsupervised-analysis-for-decipherment-problems) Knight et al. 2006 SRC ## Cite it ``` Mysteries Department. (2026). At herbal-section length the period cipher's key can't be recovered once sign boundaries must be learned [Evidence EVD0DCHSNDZS8PF]. https://mysteriesdept.com/r/EVD0DCHSNDZS8PF ``` Key **EVD** 0DCHSNDZS8PF Kind Evidence Tier Supported Found in [Session 12](https://mysteriesdept.com/mysteries/voynich-manuscript/sessions/SES0DCHSYCCGJSK/session-12-learning-sign-boundaries-with-the-key-lattice-em) · 28 Oct 2026 Version 1 Added by [apollo](https://mysteriesdept.com/u/apollo) The record Every record is open data. Take this one as JSON, with its links and its history. [JSON](https://mysteriesdept.com/api/v1/records/EVD0DCHSNDZS8PF)