“The same key completion at periods 27 to 29, with the table rebuilt from the puzzle's words”
Experiment 34 climbed the free key letters under the standard and KRYPTOS alphabets only. Here one of the two alphabets, for the message or for the carved letters, is rebuilt from each vocabulary word, and the key alphabet is dropped, since it does not change the decryption. Periods 27 to 29 only, where the key has three to five free letters and the climb cannot overfit.
Experiment 34 showed that with a secret word of length 27, 28 or 29, filling in the few unknown letters never produces a readable message when 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. is the sculpture's own. But the table could have been built from another word, like PALIMPSEST or ABSCISSA, and that changes every letter that comes out. So we rebuild the table from each word the puzzle knows, in turn for the messagethe message The 97 letters of English that Jim Sanborn wrote and enciphered. side and for the carved side, and run the same filling game again.
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 climb
At key lengths 27 to 29 the known letters fix almost every key slot. The few free slots are filled by trying all 26 letters and keeping whatever makes the reading most like English.
the alphabets
Repeated with one alphabet rebuilt from a puzzle word and the other standard or the sculpture's: 2,232 climbs.
the verdict
The best reading scores like noise, and the same climb on a shuffled copper does just as well. With so few free slots there is nothing to overfit, and nothing to find.
2
Best candidate against the known letters
Laid out as the copper carries K4: OBKR ends the line that finishes K3, then three lines of 31. Left, as carved, the 24 known places in accent. Right, the candidate: a known place it gets right is an accent cell, one it misses is outlined. This is the lowest-loss reading that passed the original gates.
in: the copper, always the same
as carved, 97 letters; the 24 known places in accent
ECDMRIPFEIMEHNLSSTTRTVDOHW?OBKR
UOXOGHULBSOLIFBBWFLRVQQPRNGKSSO
TWTQSJQSSEKZZWATJKLUDIAWINFBNYP
VTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
OBKR ends the line that finishes K3, then three lines of 31
out: the candidate
every place read; known places in accent, misses outlined
ECDMRIPFEIMEHNLSSTTRTVDOHW?DWIV
EFUEXNARRMGFNUECOEASTNORTHEASTM
WSESLIBREUKSFOCUJPVHUNIJEFUNBER
LINCLOCKCEDWJICYBUNUIPOBOZZHUQP
checked: the known letters in place, and the reading turns back into the copper
3
How the score is made
The loss of the best candidate, part by part. Zero is solved.
Known letters missed
0 of 24, ten points each
0.00
English
the 73 free letters score -6.61; English text scores -3.6
3.01
Key
140 bits to write it down (key words are cheap, arbitrary letters 4.7 bits each); each 60 beyond 60 costs a point
1.33
Loss
of 240, the worst possible
4.34 1.8%
All 3 candidates that passed every gate, lowest loss first.
rank
missed
English
key
loss
share
1
0
3.01
1.33
4.34
1.8%
best
2
0
3.01
1.40
4.42
1.8%
3
0
3.22
1.25
4.47
1.9%
4
Walkthrough, by hand
Redo the method on a few letters with pencil and paper.
Build the alphabet from PALIMPSEST: PALIMSETBCDFGHJKNOQRUVWXYZ, and use it for the message; keep KRYPTOS for the carved letters; Vigenere.
Period 27: position 22 is E, index 6 in the PALIMPSEST alphabet; carved F is index 11 in KRYPTOS; the key index is 5.
Do this for all 24 known letters; positions 22 and 49 share slot 21, but 49 is unknown, so no clash.
Three slots stay free.
Try every letter in each free slot in turn, decrypting the whole text each time, and keep the one that makes the 73 unknown letters read most like English.
Compare the best text's score with English, about -3.6, and with what the same game gives on shuffled letters, about -6.8.
the worksheet: the first steps by hand, on squared paper
5
Worked example, generated
The same steps run by the code on the real letters.
plain alphabet PALIMPSEST/keyword PALIMSETBCDFGHJKNOQRUVWXYZ; cipher alphabet KRYPTOS; Vigenere; period 27; 3 free slots climbed
key indices [10, 20, 6, 7, 25, 1, 25, 11, 14, 11, 22, 10, 20, 1, 14, 9, 23, 21, 20, 11, 18, 6, 16, 22, 15, 4, 3]
text VJUUWMZUZIZTJSOBQOJXSEASTNORTHEASTUNGBDGKEXCNEJTOOBAWJFNCPYJUAUBERLINCLOCKSTUMDUAEKMBJZWITWZAEBRQ
English of the free letters -8.243 (English about -3.6, noise about -6.8)
6
Hypothesis, for a cryptanalyst
Family, key space, the constraint under test, and the clues it reads.
At periods 27-29 the cribs force 24 of the key slots and leave 3-5 free, so the English climb of experiment 34 is close to exhaustive and cannot overfit; it found noise under the 8 distinct plain-cipher alphabet classes of the 24 conventions. The key alphabet only relabels the key and never changes the decrypted text, so the real variable is the pair of plain and cipher alphabets. Scheidt's keyword alphabets (C5) and the K1-K2 precedent make a table built from a puzzle word the natural extension: here one of the pair is standard or KRYPTOS and the other is the keyword mixing of any of 61 vocabulary words, both ways round, under three modes: 756 classes, 3 periods, five restarts each. The best free-letter English per class and period is compared with the same climb on one shuffle of K4. A true periodic cipher on such a table would give a text near -3.6 at its period; shuffled K4 gives about -6.8. Bounds: complete for this alphabet pool at periods 27-29; both alphabets mixed from words at once is not covered.
7
Prediction
Written before the run; the result decides it.
No class and period gives a text better than -5.5 per quadgram; the best over all 2,268 climbs is within 0.4 of the best on shuffled K4. Candidates pass the gates by construction but none reads as English; none beats the current champion's fitness.
8
Method
Build the alphabet pool: standard, KRYPTOS and the keyword mixing of each vocabulary word.
For each pair with one side standard or KRYPTOS, each mode and each period 27-29, force the 24 key slots from the cribs; skip the pair if two cribs disagree on a slot.
Climb the free slots by coordinate descent on the English score of the 73 non-crib letters, five restarts.
Keep the best text per period and submit it.
Repeat on one shuffle of K4 for calibration.
9
Result and bounds
The harness's record: candidates, gates, loss, and the negative result this experiment leaves behind.