“F5.1: Gromark with multiplicative feedback (each digit the product of two earlier ones) on a free mixed alphabet, bases 2-16 and 26, every primer: exact; YAR as a primer by subsumption”
F5.1. Every Gromark rule tested so far adds earlier digits. Here d[i] = d[i-a] * d[i-b] mod B, 1 <= a < b <= 6, every primer, bases 2-16 (base 26 with b <= 5: lag 6 is 1.5 billion primers), four forms, a free mixed alphabet, with 0195's compiled decider in product mode. YAR as a primer (Y A R as 24 0 17 in base 26, or any digits) is one of the primers every exhaustive sweep already enumerates (0076 two-term base 26, 0195 three-term base 26), so it is closed by subsumption.
A variation of the GromarkGromark A cipher whose secret is a short number that grows into a long stream of digits by adding pairs of earlier digits; each message letter is pushed along the alphabet by the next digit. key: each new digit is the product, not the sum, of two earlier digits. We try every base from 2 to 16 and 26, every pair of earlier positions up to six back, every set of starting digits, with any mixed alphabet.
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
Every Gromark rule tried so far adds earlier digits. Multiplying them is the other simple rule, and the raised YAR has been read as starting digits.
the check
Every pair of earlier positions up to six back, every base from 2 to 16 and 26, every starting run, four ways of applying the digit, any mixed alphabet.
the bound
Nothing fits K4 or a scrambled copy; planted texts are found. F5.1 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.
Base 10, rule 'multiply the digits 2 and 5 places back', primer of 5 digits.
The digit stream often collapses to zeros; then the key is constant and K4's three different carved letters under the known E rule it out at once.
Otherwise the same checks as the additive Gromark: equal known letters must land on equal slots.
Every primer, rule, base and form; then 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.
base 10, each digit the product of the digits 2 and 5 places back, primer 3 7 9 1 4:
3 7 9 1 4 3 8 7 8 8 4 4 8 2 4 8 6 4 2 6 6 6 4 2 4 2 4 8 8 2 6 8 8 4 6 4 8 2 2 2
5
Hypothesis, for a cryptanalyst
Family, key space, the constraint under test, and the clues it reads.
F5.1 (low value: no creator remark points here), C22(a) (YAR as a primer). Model as 0107/0195 with the recurrence multiplicative. Statistic: consistent (rule, primer, form) settings, K4 against 10 copies; plants.
6
Prediction
Written before the run; the result decides it.
No setting consistent on K4 or the copies. Zero candidates.
7
Method
For each base, rule and form: equal-letter pairs fix digit differences (or kill the form).
Every primer (compiled, 4 processes), product recurrence, pair checks, then the one-to-one check.
K4, 10 shuffled copies, 2 planted texts.
8
Result and bounds
The harness's record: candidates, gates, loss, and the negative result this experiment leaves behind.