Matt Ruckman

I'm Matt. I live in Seattle with my two cats who run the place. Professionally I build machine learning systems. Unprofessionally I fall into rabbit holes and build things at the bottom.

The papers are deep dive. The blog posts are long and probably have too many footnotes. The projects are what happens when "I wonder if..." turns into three weeks.

Latest Post

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May 29, 2026·cryptography

The Answer In The Box

The first two pieces in this series were about ciphers nobody can read. This one is about a cipher whose answer we finally have, sitting in a sealed box until 2075, that we still can't read either, and about the century of work that took the lock, printed the design on the outside, and built it so well that knowing the design didn't help.

Latest Paper

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May 2026

Kryptos K4 at its Unicity Distance: A Homophonic Reframe and a Model-Robust Under-Determination Result

A deterministic, decipherment-only cryptanalysis of Kryptos K4 (125 experiments, 86 logged verdicts) that stops short of a decryption and instead proves a sharp structural result: K4's free positions are under-determined by the public inputs, pending exactly one external fact. The four cribs leave the 30 selector-locked positions at a provable per-position coin flip.

cryptanalysiskryptosk4homophonic-cipherunicity-distanceunder-determination
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Latest Project

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Kryptos K4 Attack Harness

GitHub ↗

A cipher library and experiment harness for attacking Kryptos K4, the 97-character ciphertext that has resisted for 35 years. 42 experiments plus LLM plaintext-inference and evolutionary mutation search returned zero solves; the key result is structural: the four confirmed cribs alone force any valid K4 cipher to use at least three distinct alphabets.

pythoncryptanalysiskryptosk4researchunsolved-ciphers