Fractionation

Methods that break each letter into smaller pieces (like grid coordinates), scramble those pieces, then reassemble them into new letters. Includes Bifid, Playfair, Four-Square, and ADFGVX.

What we tested: Bifid, Playfair, ADFGVX, and related ciphers are all impossible for K4 because they require merging I and J into a single letter (using a 25-letter alphabet), but all 26 letters appear in K4's ciphertext. This is a permanent mathematical impossibility, not just a search result.

19 eliminations recorded.

Title	Configs	Best	Verdict	Tier
K2 coordinates as straddling checkerboard configuration K2 coordinates as straddling checkerboard configuration — using a method that encodes letters as variable-length digit sequences. 9.2 million key/para…	9,223,974	0/24 (0.0)	NOISE	Tier 4
Straddling checkerboard digit-level attack on K4 Straddling checkerboard digit-level attack on K4 — using a method that encodes letters as variable-length digit sequences. 86 thousand key/parameter c…	86,066	0/24 (0.0)	NOISE	Tier 4
Non-algebraic process-based ciphers on 5-wide KA Polybius grid Non-algebraic process-based ciphers on 5-wide KA Polybius grid — using a method that converts letters to number pairs using a grid (Polybius square). …	17,262	0/24 (0.0)	NOISE	N/A
Modified Polybius Grids Modified Polybius Grids — using a method that converts letters to number pairs using a grid (Polybius square). 8 thousand key/parameter combinations w…	8,374	0/24 (0.0)	NOISE	N/A
Morse code misspellings produce grid cipher key material; straddling checkerboard explains 73->97 expansion Morse code misspellings produce grid cipher key material — using a method that encodes letters as variable-length digit sequences. 535 key/parameter c…	535	5/24 (0.0)	NOISE	Tier 4
Bifid 5x6 Ka Bifid 5x6 Ka — using a method that breaks letters into grid coordinates, mixes them, and reassembles (Bifid cipher).	N/A	7/24 (0.0)	NOISE	N/A
Bifid cipher (algebraic proof of impossibility) Bifid cipher algebraic impossibility proof — all 26 letters present in K4 CT — using a method that breaks letters into grid coordinates, mixes them, a…	N/A	0/24 (0.0)	ELIMINATED	Tier 1
Bifid 6x6 at periods 2-49 (algebraic contradiction analysis) Bifid 6x6 at periods 2-49 (algebraic contradiction analysis) — using a method that breaks letters into grid coordinates, mixes them, and reassembles (…	N/A	0/24 (0.0)	NOISE	N/A
Bifid 6x6 cross-group algebraic elimination for periods 9-14 Bifid 6x6 cross-group algebraic elimination for periods 9-14 — using a method that breaks letters into grid coordinates, mixes them, and reassembles (…	N/A	0/24 (0.0)	NOISE	N/A
Polybius-coordinate cipher exploit: running-key + SA Polybius-coordinate cipher exploit: running-key + SA — using a method that converts letters to number pairs using a grid (Polybius square).	N/A	0/24 (0.0)	NOISE	N/A
Polybius fractionation as inner cipher + null mask as outer layer Polybius fractionation as inner cipher + null mask as outer layer — using a method that converts letters to number pairs using a grid (Polybius square…	N/A	0/24 (0.0)	NOISE	N/A
Polybius Row Clustering Audit Polybius Row Clustering Audit — using a method that converts letters to number pairs using a grid (Polybius square).	N/A	0/24 (0.0)	NOISE	N/A
Polybius Split Coordinate Polybius Split Coordinate — using a method that converts letters to number pairs using a grid (Polybius square).	N/A	0/24 (0.0)	NOISE	N/A
Row gradient validation for keystream present/absent values on KA Polybius grid Row gradient validation for keystream present/absent values on KA Polybius grid — using a method that converts letters to number pairs using a grid (P…	N/A	0/24 (0.0)	NOISE	N/A
Row-Markov regularized keystream SA: 4 conditions testing whether Polybius row structure helps decode K4 Row-Markov regularized keystream SA: 4 conditions testing whether Polybius row structure helps decode K4 — using a method that converts letters to num…	N/A	0/24 (0.0)	NOISE	N/A
Polybius Row Selection Mask Polybius Row Selection Mask — using a method that converts letters to number pairs using a grid (Polybius square).	N/A	0/24 (0.0)	NOISE	N/A
Playfair Playfair — using a method that encrypts pairs of letters using a 5×5 grid (Playfair cipher).	N/A	0/24 (0.0)	ELIMINATED	N/A
S 42b S 42b — using a method that breaks letters into three-part coordinates and recombines them (Trifid cipher).	N/A	0/24 (0.0)	NOISE	N/A
S S — using a method that breaks letters into three-part coordinates and recombines them (Trifid cipher).	N/A	0/24 (0.0)	ELIMINATED	N/A