Self-keying (autokey) cipher with short starting keys, alone or with a width-8 column shuffle

26 one-letter and 25 short word or letter-group starting keys, in six forms (plaintext- or ciphertext-keyed Vigenere, Beaufort or Variant Beaufort) on the standard and KRYPTOS alphabets. Each was applied directly to the carved text, and then with every width-8 column order added before or after the self-keying step, for the 10 best direct settings and for all 26 one-letter starting keys. Best result: 9 of 24 known letters (4 of 24 without the column shuffle). An older summary of this run reported 21 of 24; re-running the script on 2026-09-29 gives 9.

In plain English: 26 one-letter and 25 short word or letter-group starting keys, in six forms (plaintext- or ciphertext-keyed Vigenere, Beaufort or Variant Beaufort) on the standard and KRYPTOS alphabets, using a self-keying (autokey) method, where the key starts with a short word and then continues with letters of the message itself. 26.0 million key/parameter combinations were tested. This record is negative within the tested scope.

ELIMINATED Tier 3

How to read this record

Verdict – ELIMINATED (ruled out within the tested scope), NOISE (nothing beyond what chance produces for a search of this size; also shown when a record stored no verdict of its own), INCONCLUSIVE (the test left candidates or options standing, or could not decide, so it does not rule the method out), 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, valid while its stated assumptions hold. Tier 2 = every possibility within the stated scope tested. Tier 3 = partially tested or sampled. Tier 4 = not yet properly 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). N/A means no such score could be read from this record.
Keystream Consistency (Bean) – Whether the key values at different positions are mathematically consistent with each other. The check only holds when the known letters stay in their carved positions (no letters rearranged or removed), and the full set used here assumes the standard A to Z alphabet.
Scope Limitations – What this elimination does not rule out.

Configs Tested: 25,966,692
Best Score: 9 / 24 known letters matched · low, no sign of a solution
Confidence: Tier 3: Partial or statistical. May warrant re-testing under different assumptions.
Date Tested: 2026-02-19
Script: scripts/polyalphabetic/e_chart_02_autokey.py

Scope Limitations

This elimination does not rule out:

Starting keys other than the 51 tried here, and column shuffles at widths other than 8, except where the separate check below applies
Starting keys longer than 25 letters: a separate check shows that self-keying applied directly to the carved text (no rearrangement), in all three forms on the standard or KRYPTOS alphabet, cannot match all 24 known letters when the starting key is 25 letters or fewer, but it does not cover longer starting keys
Self-keying combined with a general letter rearrangement: the separate check does not cover it, and an unrestricted rearrangement leaves too much freedom for the known letters to rule it out

Assumptions

Known letters at their standard positions
Width-8 columnar transposition filled row by row and read column by column

Reproduce

PYTHONPATH=src python3 -u scripts/polyalphabetic/e_chart_02_autokey.py

Requires the kryptos repo, Python 3.11+, PYTHONPATH=src. Some recent scripts may not be in the public repository yet.

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