Gap-9 differential filter for running key identification
EAST repetition constraint mining — gap-9 differential filter for running key identification
In plain English: EAST repetition constraint mining — gap-9 differential filter for running key identification — using a passage from a book or document as the encryption key. Every possible combination was tested (4.0 million 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
- 4,000,000
- Best Score
- 0 / 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
[DERIVED FACT]- Date Tested
- 2026-02-27
- Script
scripts/cfm/e_cfm_06_east_constraint.py
Scope Limitations
This elimination does not rule out:
- Filter only works under identity transposition. Under arbitrary transposition, EAST diffs change per permutation.
Assumptions
- Additive substitution (Vigenere/Beaufort/VB)
- Running key from contiguous text passage
Related Research Questions
Reproduce
PYTHONPATH=src python3 -u scripts/cfm/e_cfm_06_east_constraint.pyRequires the kryptos repo, Python 3.11+, PYTHONPATH=src.
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