Autokey cipher on 73-char column mask extract (all variants)

Tested autokey (PT/CT feedback × Vig/Beau/VBeau × AZ/KA), progressive key, running key on 73-char column mask extracts from the 28×31 native grid null band. 46,170 configs across 9 keep-column variants. Max 6/24 = NOISE. This is a DIFFERENT test from autokey on raw 97, shifted crib positions (ENE at 13-25, BC at 47-57) and different ciphertext.

In plain English: Tested autokey (PT/CT feedback × Vig/Beau/VBeau × AZ/KA), progressive key, running key on 73-char column mask extracts from the 28×31 native grid null band — using a method that replaces each letter using a repeating keyword (Vigenère cipher). Every possible combination was tested (46 thousand configurations) — none produced a valid solution. This approach is ruled out within the tested scope.

NOISE Tier 2

How to read this record

Verdict – NOISE (no better than random guessing), INTERESTING (slightly above random, almost certainly coincidence), SIGNAL (statistically unusual, warrants investigation), or FULL MATCH (all 24 known letters correct).
Confidence Tier – Tier 1 = mathematical proof (permanent). Tier 2 = every possibility tested. Tier 3 = partially tested. Tier 4 = not yet tested.
Configs Tested – How many different key/parameter combinations were tried.
Best Score – How many of the 24 known plaintext letters the best attempt matched (out of 24).
Keystream Consistency (Bean) – Whether the key values at different positions are mathematically consistent with each other.
Scope Limitations – What this elimination does not rule out.

Configs Tested: 46,170
Best Score: 6 / 24 known letters matched · no better than random guessing (random guess would score: 0.0)
Keystream Consistency (Bean): FAIL
Checks whether the key values at different positions are mathematically consistent with each other.
Confidence: Tier 2: Exhaustive search under stated assumptions. Does not eliminate multi-layer variants.
Truth Tag: [INTERNAL RESULT]
Date Tested: 2026-03-12

Scope Limitations

This elimination does not rule out:

Only tests autokey on column-mask-extracted 73-char text. Other null mask patterns untested with autokey. Running key from limited dictionary only.

Assumptions

Column mask removes cols 8-16 minus one kept col
Shifted crib positions
Standard autokey PT/CT feedback

Reproduce

PYTHONPATH=src python3 -u scripts/grille/e_column_mask_autokey_01.py

Requires the kryptos repo, Python 3.11+, PYTHONPATH=src.

Found an error? Report on GitHub