“F6.9: ciphertext and plaintext autokey, every lag, joined to 0084's double columnar routes (one stage of width 7 in all 5,040 orders), either order, on the sculpture's tables”
F6.9 (pivot audit, issue #55, D11). 0084 joined double columnar routes with one stage of width 7 in all 5,040 column orders to a repeating key; 0081 joined autokeys to the type-1 library. Here the two meet: the same routes (a width-7 stage in every order, the other a plain columnar of width 2-30 or a puzzle-word columnar, either first, forward and inverse, deduplicated) with ciphertext or plaintext autokey at every lag 1-96, the autokey after the move (on the moved stream) or before it, one alphabet throughout (standard or KRYPTOS), three rules. On a fixed table every check is a direct comparison; compiled; ten scrambled coppers.
revertedstatus
a new rootparents
6 mintime, all phases
0candidates
0/24known letters
unclocked
1
The experiment method
What the method does with the 24 known letters.
An autokey cipheran autokey cipher A cipher that uses the message itself, or the scrambled text itself, as the secret word, each letter enciphered with the letter a fixed distance before it. uses the messagethe message The 97 letters of English that Jim Sanborn wrote and enciphered., or the enciphered text, as its own key, a fixed number of letters back. Here it is combined with a double grid move in which one grid is seven wide (KRYPTOS has seven letters, and K4the carved letters The 97 letters cut into the copper at the CIA, shown at the top of every experiment page.'s doubled lettersthe doublets Places where a carved letter is immediately followed by the same letter. line up in sevens), in every column order. On the sculpture's tables each known letter can be checked directly, for every distance back, on the carved text and scrambled copies.
Words in the margin are defined on the glossary page.
1.1
The method at work
The carved letters go in at the top; the reading comes out at the bottom.
the idea
K4's doubled letters line up in sevens and KRYPTOS has seven letters; the NSA guessed plaintext autokey. Here autokey meets grid moves in which one grid is seven wide, in every column order.
the check
5,040 width-7 column orders with 163 second grids, either first, both directions; ciphertext or plaintext autokey at every lag, after or before the move, on the sculpture's tables; every check is direct.
the bound
Settings that pass five or more checks are as common on K4 as on scrambled copies, in all four forms. Closed.
2
Best candidate against the known letters
This experiment produced no candidate: the search ruled everything out before a full text was built. Its product is the bounded negative in section 7.
3
Walkthrough, by hand
Redo the method on a few letters with pencil and paper.
Write the message in rows of 7 and read the columns in some order, say 3 1 6 0 4 2 5; then write it in rows of 12 and read down the columns.
Encipher the moved text by ciphertext autokey at lag 8: each letter's key is the carved letter 8 places before.
At each known letter's landing place, look up the carved letter there and the one 8 before: the table says which message letter that pair gives; it must be the known letter.
Repeat for every order, width, lag, table and form, and on scrambled copies.
the worksheet: the first steps by hand, on squared paper
4
Worked example, generated
The same steps run by the code on the real letters.
rows of 7 read in column order 3 1 6 0 4 2 5, then rows of 12 read down; ciphertext autokey at lag 8 after the move
place letter lands at carved carved 8 before
22 E 69 T N
23 A 43 S O
24 S 7 X -
64 B 22 F S
65 E 91 A C
5
Hypothesis, for a cryptanalyst
Family, key space, the constraint under test, and the clues it reads.
C11a (NSA 1992: 'plain-text auto-key' and 'interval 7', knowledge/sources/nsa-foia-1992-2014-blackvault-compilation.txt), C8(a) (KRYPTOS's seven letters as a column key), directions.md type 2 (sevens: the width-7 doublet column, 0056). Model: A move then autokey: c_j = T(y_j, k_j), k_j = c_{j-L} (ciphertext) or y_{j-L} (plaintext); B autokey then move: e_i = T(p_i, k_i), k_i = e_{i-L} or p_{i-L}, c_{M(i)} = e_i. Checks: every known letter whose key letter is known (always for ciphertext autokey past the primer; for plaintext autokey when the key's place is a known letter). A setting survives if every check agrees. Statistic fixed before the run (0081's): survivors with five or more checks per (kind, order), K4 against the coppers' range.
6
Prediction
Written before the run; the result decides it.
Survivors with five or more checks at the coppers' rate in every kind and order (0081 found none with five on the type-1 library). Zero candidates.
7
Method
Stage maps: the 5,040 width-7 orders; second stages plain columnar 2-30 and puzzle-word columnar.
Compiled: compose both orders, forward and inverse, deduplicate; for each route, lag, table and rule, the four autokey forms; count survivors by checks.
K4 against the coppers.
8
Result and bounds
The harness's record: candidates, gates, loss, and the negative result this experiment leaves behind.
0candidates returned
0passed every gate
0/24known letters, best
–lowest loss
nonechampion before
A ciphertext autokey: >=5 checks K4 0 (coppers 0-8); A plaintext autokey: >=5 checks K4 9 (coppers 5-21); B ciphertext autokey: >=5 checks K4 1 (coppers 0-1); B plaintext autokey: >=5 checks K4 0 (coppers 0-480)
What was searched, as the harness recorded it.
family
ciphertext and plaintext autokey at lags 1-96, one alphabet (std or KRYPTOS), 3 rules, after or before 0084's width-7 double columnar routes
width7 orders
5,040
second stages
163
second stages done
163
distinct routes
3,284,523
duplicates skipped
1,557
summary
A ciphertext autokey
k4 ge5
0
coppers ge5
3, 2, 0, 0, 8, 0, 0, 0, 1, 8
k4 ge4
99
coppers ge4
76, 97, 136, 297, 118, 124, 82, 77, 153, 103
k4 max checks survivor
4
A plaintext autokey
k4 ge5
9
coppers ge5
5, 21, 11, 21, 10, 6, 10, 9, 9, 11
k4 ge4
422
coppers ge4
359, 474, 427, 504, 425, 480, 415, 403, 509, 334
k4 max checks survivor
5
B ciphertext autokey
k4 ge5
1
coppers ge5
0, 1, 0, 1, 0, 1, 1, 0, 0, 1
k4 ge4
31
coppers ge4
95, 23, 24, 44, 40, 46, 42, 197, 18, 19
k4 max checks survivor
5
B plaintext autokey
k4 ge5
0
coppers ge5
0, 2, 0, 480, 5, 4, 0, 0, 2, 0
k4 ge4
180
coppers ge4
766, 66, 568, 516, 169, 34, 64, 80, 176, 44
k4 max checks survivor
4
seconds
256
controls
10 shuffled coppers (seed 1609)
exhaustive
exact for every second stage done
How this experiment sits among the others is on the lineage page; its family's open hypotheses are on the families page.
Rendered from the record on 2026-10-18 12:26 UTC; updated after every experiment.