Experiment 145

“F1.2 at key length 8: design 2 on two free alphabets, its power on planted English against copies that keep the known places (0143's unfinished cell)”

F1.2 at length 8 alone. In 0143 the length-8 texts ran last and 27 of 30 finished no search before the deadline, so that cell had no verdict. Same search, same copies (carved letters kept at the 24 known places), sized to finish: 4 planted texts, 4 copies each (20 texts at about 200-400 s each).

revertedstatus
experiment 143parents
12 mintime, all phases
0candidates
0/24known letters
unclocked
1

The experiment method

What the method does with the 24 known letters.

The search that notices planted English under one scrambled alphabet is extended to two scrambled alphabets, one for the messagethe message The 97 letters of English that Jim Sanborn wrote and enciphered. and one for the carved lettersthe carved letters The 97 letters cut into the copper at the CIA, shown at the top of every experiment page., and checked on planted English at three key lengths. Each planted message is compared with copies that keep the letters at the 24 known places and scramble the rest, so only the order of the other letters differs. If it notices the English often enough, it may judge the carved text at that length.

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.

OBKRUOXOGHULBSOLIFBBWEASTNORTHEASTOTWTQSJQSSEKZZWATJKLUDIAWINFBBERLINCLOCKWGDKZXTJCDIGKUHUAUEKCARIN: THE COPPER, ALL 97 LETTERS, THE 24 KNOWN PLACES IN ACCENTtwo unknown alphabets, key length 8 (16 checks): each cell a planted text against 4 copies keeping the known places1234beats all its own copiesdoes not4 of 4; bar 3; luck 0.8every search finished (10 runs per text); best readings 39-47 of 97 letters right, none recoveredOUT: NO READING; DESIGN 2 HAS POWER WITH TWO ALPHABETS AT LENGTH 8 TOOEASTNORTHEASTBERLINCLOCK
the idea

0143's length-8 cell never finished: its texts ran last and the clock ran out. Here it runs alone, sized to finish.

the check

Four planted English texts enciphered with two random alphabets and an 8-letter key, each against four copies that keep the carved letters at the 24 known places.

the bound

4 of 4 beat all their copies (bar 3): the search can judge length 8. K4 at 8 is next.

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.

  1. Encipher a passage of English with two random alphabets and a random key of length 8, known words in place.
  2. Make five copies that keep the carved letters at the 24 known places and shuffle the other 73.
  3. Find one pair of alphabets that gives all 24 known letters; it works for the copies too, since their known places are the same.
  4. Run sixteen searches side by side from that pair, swapping letters within either alphabet while every check holds, scoring the whole text as English.
  5. The planted text is noticed if it beats all five copies; luck gives that one time in six.
the worksheet: the first steps by hand, on squared paper
TWO ALPHABETS, KEY LENGTH 8: EACH PLANTED TEXT AGAINST ITS FOUR COPIESplantits bestbest copyrank of 5letters right1-5.30-5.541412-5.31-5.461393-5.24-5.271474-5.25-5.37143At length 8 every one of the 8 key slots holdsknown letters: 16 checks tie the two alphabetstogether, and the search moves only betweenpairs that keep all 16.
4

Worked example, generated

The same steps run by the code on the real letters.

key length 23, Beaufort form: K4 in rows of 23; each column is one key slot

  O B K R U O X O G H U L B S O L I F B B W F L
  R V Q Q P R N G K S S O T W T Q S J Q S S E K
  Z Z W A T J K L U D I A W I N F B N Y P V T T
  M Z F P K W G D K Z X T J C D I G K U H U A U
  E K C A R

the seven checks every move keeps (place(carved) + place(known) equal within a column):
  column 0: R+S (24) = M+C (70)
  column 1: V+T (25) = Z+L (71)
  column 2: Q+N (26) = F+O (72)
  column 3: Q+O (27) = P+C (73)
  column 4: P+R (28) = K+K (74)
  column 21: F+E (22) = T+I (68)
  column 22: L+A (23) = T+N (69)
5

Hypothesis, for a cryptanalyst

Family, key space, the constraint under test, and the clues it reads.

C27(c) (the 'slightly different' tableau), C1(b). Model: 0123's Quagmire IV, two unknown bijections P, C, key length 8, 16 checks. Search: replica exchange, 16 replicas, T 0.1 -> 0.002, 10 runs x 625 rounds x 1,000 moves per text (0139's effort), moves swap two places in one alphabet, repaired by a second swap when a check breaks; full-text quadgram mean. Power: 4 planted texts (seed 145), each against 4 copies keeping the 24 known places (seed 1451); null 1/5 per plant (0.8 of 4). Bar fixed before the run: at least 3 of 4 beat all their own copies. A passing length gets K4 against copies of K4 kept the same way in the next run; a failing length stays blocked (no power).

6

Prediction

Written before the run; the result decides it.

With 16 checks the climb is held tightest; at least 3 of 4 plants beat all their own copies (13 and 16 passed in 0143). No planted text recovered. Zero candidates.

7

Method

  1. 5 planted Quagmire IV texts per length and 5 kept-place copies of each.
  2. 0123's decider gives each plant an exact witness; it starts the plant and its copies.
  3. The compiled two-alphabet tempering search on all 90 texts; decryption checked against Python.
  4. Per length: plants beating all their own copies.
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

Quagmire IV power: L8 4/4 (16 checks); runs per text 10-10

What was searched, as the harness recorded it.

family
two free alphabets (Quagmire IV), periodic key 8, 13, 16, no move: power of design 2 on planted English
search
parallel tempering, 10 runs x 16 replicas x 625 rounds x 1000 moves per text, T 0.1->0.002; start from the plant's exact witness (0123) randomised by 400 check-keeping swaps
not exhaustive
yes
runs done
min
10
max
10
texts with no finished run
0
c decryption checked
yes
copies
keep the carved letters at the 24 known places, shuffle the other 73 (fit by construction)
bar
>= 3 of 4 plants beat all 4 own copies (null 0.80)
by length
8
checks
16
found
4
passes bar
yes
rows
  1. score
    -5.3
    letters right
    41
    runs
    10
    own copies
    -5.852, -5.784, -5.611, -5.54
    rank among own
    1
    found own
    yes
    recovered
    no
  2. score
    -5.311
    letters right
    39
    runs
    10
    own copies
    -5.951, -5.93, -5.728, -5.463
    rank among own
    1
    found own
    yes
    recovered
    no
  3. score
    -5.239
    letters right
    47
    runs
    10
    own copies
    -5.644, -5.575, -5.481, -5.272
    rank among own
    1
    found own
    yes
    recovered
    no
  4. score
    -5.251
    letters right
    43
    runs
    10
    own copies
    -5.707, -5.504, -5.489, -5.37
    rank among own
    1
    found own
    yes
    recovered
    no
controls
per plant, 4 kept-place copies (seed 1451)

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.
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