“Long keys with a shape: two puzzle words joined, a word and its mirror, a word doubled, at the periods the cribs allow”
Experiment 5 matched the forced key fragments at periods 27 to 29 against single vocabulary words and K1-K3 windows. A 27 to 29 letter key is unlikely to be one word; here it is built from two: joined, joined with a separator letter, a word followed by its mirror, or a word doubled. The forced fragments are matched exactly under the standard, KRYPTOS and vocabulary-mixed alphabets.
A secret word of 27 to 29 letters is probably not one word. It could be two of the puzzle's wordsthe puzzle's words A list of 62 words tied to the sculpture: the earlier secret words, place names, the names of the people involved, the words in the Morse code, and the themes Sanborn has named. joined, a word followed by itself, or a word followed by its mirror image. Each such key fixes the 24 letters that the known lettersthe known letters Sanborn has confirmed that positions 22 to 34 of the message read EASTNORTHEAST and positions 64 to 74 read BERLINCLOCK. demand, so we simply build every key of that kind and check it against the 24 demands, on the sculpture's tablethe table The right-hand half of the sculpture, 26 rows of the alphabet each shifted one place further, starting from the word KRYPTOS. and on tables rebuilt from the puzzle's words.
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 forced slots
At period 27, on the sculpture's table, each known letter forces the key letter in its slot (place p uses slot p mod 27); three slots stay free.
the shapes
A 27 to 29 letter key is unlikely to be one word, so the experiment built 272 keys from the puzzle's words: two joined, joined with an X or a Q, a word and its mirror, a word doubled.
the bound
9,716,112 trials over every shaped key, 63 x 63 tables, three modes and three key readings: none comes within three misses of the forced letters.
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.
Join BERLIN and ALEXANDERPLATZ: BERLINALEXANDERPLATZ is 20 letters, too short; join WILLIAMWEBSTER and PALIMPSEST: 24, too short; join TUTANKHAMUN and SHADOWFORCES: 23.
Keep the pairs that reach 27, 28 or 29 letters, such as DIGITALINTERPRETATION joined with EGYPT.
On the sculpture's table with Vigenere, position 22 forces key letter R at slot 21 of a 27-letter key; position 23 forces D at slot 22, and so on for all 24 known letters.
Compare the joined key's letters at those slots; one mismatch and the key is out.
Repeat for every pair, every mirror and every doubling, under every table.
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.
key DIGITALINTERPRETATIONEGYPT, length 26: a 26-letter join falls short of 27, so it is not tried; take instead
joined ABSCISSA+DIGITALINTERPRETATION: ABSCISSADIGITALINTERPRETATION (29 letters)
sculpture's alphabet throughout, Vigenere: forced key letters at the first slots
pos 22: slot 21 must be R; the key has R
pos 23: slot 22 must be D; the key has E
pos 24: slot 23 must be U; the key has T
pos 25: slot 24 must be M; the key has A
5
Hypothesis, for a cryptanalyst
Family, key space, the constraint under test, and the clues it reads.
Periods 27-29 survive the crib sweep under every alphabet pair (0005, 0020), and their forced key fragments read as noise (0009, 0010), which rules out an English phrase as key but not a key made of two puzzle words with no English transition, or a word and its reverse (Sanborn's mirrors, C3), or a doubled word. Key shapes: X+Y, X+c+Y for a separator letter c, X+reverse(X), X+X, X+reverse(Y), over the 62-word vocabulary and its K1-K3 windows, kept when the length is 27, 28 or 29. Under each plain-cipher alphabet pair (standard, KRYPTOS, 61 keyword mixings) and mode, the 24 forced key indices are compared with the key read in the standard, KRYPTOS or the plain alphabet; a match decrypts and submits. About 20,000 key shapes x 12,000 alphabet classes, exact. Bounds: complete for these shapes and alphabets.
6
Prediction
Written before the run; the result decides it.
No shaped key of length 27 to 29 matches all 24 forced letters under any alphabet pair and mode. Zero candidates pass.
7
Method
Build the shaped keys of length 27-29 from the vocabulary.
For each plain and cipher alphabet and mode, compute the 24 forced key indices and their slots at each period.
For each key, read it in each key alphabet as indices and compare at the forced slots; count mismatches.
Decrypt and submit exact matches; report the fewest mismatches.
8
Result and bounds
The harness's record: candidates, gates, loss, and the negative result this experiment leaves behind.