Image: dbourdeau.github.io · A page of cipher numbers being deciphered, in pixel art
Claude Code pointed at unsolved historical ciphers
A data scientist and a community of Claude Code users attempted over 460 historical ciphers, building small solvers for each.
Credits
Earliest dated source:
The full story
The poster, a data scientist, used Claude Code to attack historical ciphers pulled from archives, and the effort grew into CYPHERSOLVER, an informal benchmark with a public write-up for each target. They say a community of 60+ users attempted 460+ ciphers in six weeks, with about 80% either solved or matched to an answer already buried in archives.
Claude built small purpose-built solvers, such as annealers and n-gram language models, for each problem. These are the poster's own claims; they say they are working with a cryptologist to validate the results for publication.
How it was done
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Sources
From a short post by the maker, so the details are as they tell them.
- Reddit: I spent 6 weeks pointing Claude Code at historical ciphers nobody had read. Here’s what workedReddit poster: AdOk8143Posted
The maker's post on r/ClaudeCode.
If it disappears: archived copy of Reddit: I spent 6 weeks pointing Claude Code at historical ciphers nobody had read. Here’s what worked (opens in a new tab)
- The project: dbourdeau.github.io
Linked in the post.