AMSCO + disrupted columnar transposition (Swapped, Nihilist)

At widths 5-8 only

In plain English: At widths 5-8 only, using a columnar transposition variant that alternates between 1 and 2 characters per cell. Every combination within the stated scope was tested (4.4 million configurations); none produced a valid solution. Best match: 15/24 known letters, a level that searches like this can reach without the right key. This record is negative within the tested scope.

NOISE Tier 2

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: 4,435,200
Best Score: 15 / 24 known letters matched · can occur by chance in searches like this
Confidence: Tier 2: Exhaustive search under stated assumptions. Does not eliminate multi-layer variants.
Date Tested: 2026-02-15
Script: scripts/transposition/other/e_s_22_amsco_disrupted.py

Scope Limitations

This elimination does not rule out:

Covers AMSCO (1-2 alternating), Nihilist transposition and swapped columnar at widths 5 to 8 only (the script skipped widths 9 to 14 as too large), with a repeating-key Vigenere or Beaufort at key lengths 3 to 8, in both layer orders. Its Bean check was applied after the transposition had moved the known letters, which is not valid (see the 2026-08-24 Bean-frame retraction), so the result rests on the match scores alone.

Assumptions

Repeating-key substitution (Vigenere or Beaufort) at key lengths 3 to 8
Substitution before or after the transposition
Standard AMSCO alternating fill pattern

Reproduce

PYTHONPATH=src python3 -u scripts/transposition/other/e_s_22_amsco_disrupted.py

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

Found an error? Report on GitHub