“The earlier messages as a running key, on tables rebuilt from the puzzle's words”
Experiment 4 slid the K1-K3 plaintexts and ciphertexts past K4 under the standard and KRYPTOS alphabets. Here the plain and cipher alphabets are the keyword mixings of every vocabulary word, with the key letters read on the standard or KRYPTOS order.
Experiment 4 asked whether the first three messagesthe earlier messages The three solved parts of the sculpture., lined up under the fourth as a long secret word, could explain 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., using the sculpture's own table. The tablethe table The right-hand half of the sculpture, 26 rows of the alphabet each shifted one place further, starting from the word KRYPTOS. might have been built from another word, so we rebuild it from each word the puzzle knows and slide the three messages past the fourth again, at every starting point, forwards and backwardsa mirror Reading or writing the text from the end to the start..
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 key row
A running key is a long text written under the message, one letter per place. Drawn here: the K1 solution, with the BERLIN alphabet for the message and the CLOCK alphabet for the copper.
the rule
The search slides the text one letter at a time along the message, forwards and backwards; three misses among the 24 known places end an offset.
the bound
146,932,380 trials over every offset, both directions, every table pair and three modes: no offset comes within two misses.
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.
Build the alphabet from BERLIN for the message letters and from CLOCK for the carved letters.
Lay the K1 plaintext under the fourth message starting at some offset, so each position has a key letter.
Position 22 is E: find E in the BERLIN alphabet, add the key letter's place in the plain alphabet, and read the result in the CLOCK alphabet; compare with the carved F.
A miss counts one; three misses end this offset.
Slide the offset along the whole text, then reverse the text, then try the next pair of alphabets.
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.
(worked_example failed: IndexError('string index out of range'))
5
Hypothesis, for a cryptanalyst
Family, key space, the constraint under test, and the clues it reads.
Sanborn's 'clues to the last section are contained in previously deciphered parts' (C7) read as a running key was killed under 24 conventions in experiment 4. Under keyword-mixed plain and cipher alphabets (C5, C29) every trial changes, so the sweep is rerun: sources are the K1, K2 (as carved and corrected) and K3 plaintexts, the three ciphertexts, and the concatenations of each set, read forward and backward at every cyclic offset; 63 plain x 63 cipher alphabets x 2 key alphabets x 3 modes; mismatches counted with early exit at three. Chance survival per trial is 26 to the minus 24, with about 180 million trials. Bounds: complete for these texts and alphabets.
6
Prediction
Written before the run; the result decides it.
No text, offset, direction or alphabet pair explains all 24 known letters, and none comes within two mismatches. Zero candidates pass.
7
Method
Build the key texts and the alphabet pool.
For each plain and cipher alphabet, key alphabet and mode, precompute the cipher letter for every (plain, key) pair.
For each text, direction and offset, count mismatches at the 24 cribs, stopping at the third.
Keep trials within two mismatches; decrypt and submit any with zero.
8
Result and bounds
The harness's record: candidates, gates, loss, and the negative result this experiment leaves behind.