I built a toy Bitcoin-like chain where the ledger lives in a GitHub README and mining is subset-sum instead of hashing

I’ve been working on a small experiment to run a chain that’s deliberately Bitcoin-shaped inside a github repo.

Blocks live in chain/blocks.jsonl. You mine on your machine, paste a submission as an issue comment, and a GitHub Action validates and appends it. The README re-renders from the chain file . Anyone can replay from genesis with a verify.py script.

Proof of work is subset-sum, Same compact bits / chainwork / retarget machinery as Bitcoin, but a valid block carries k solved subset-sum puzzles (meet-in-the-middle, n=40). Difficulty scales by requiring more puzzles per block, not bigger hashes.

Everything else is intentionally familiar:

• UTXOs, secp256k1 ECDSA (RFC 6979, low-s)
• 50-coin subsidy, halving every 210 blocks
• Retarget every 16 blocks, 10-minute target spacing

• Coinbase maturity, median-time-past, merkle roots

• Repo: https://github.com/ram0verflow/ram0verflow

• Explorer (verifies in your browser): https://ram0verflow.github.io/ram0verflow/

• Spec: https://github.com/ram0verflow/ram0verflow/blob/main/SPEC.md

• Mine a block (issue #1): https://github.com/ram0verflow/ram0verflow/issues/1