The ledger
A blockchain, built from scratch
Signed transactions, proof-of-work blocks, Merkle proofs, a mempool and peer-to-peer sync, written in Python. It records one thing: fingerprints of the receipts I issue.
Latest blocks
Each block is locked to the one before
A block's hash covers the hash of the block before it. Change any old block and every hash after it stops matching.
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#0
Genesis
887fc8ebaaf121895e75ac8d3ae89fac52932e1dd0d5c08462274c57354945b7
How it works
From a payment to a provable receipt
Fingerprint
The receipt's data fields are hashed with SHA-256. Only that hash leaves the database; names and amounts stay private.
Sign
The hash becomes a transaction signed with my private key using ECDSA on the secp256k1 curve.
Mine
The transaction waits in the mempool until a miner finds a nonce that gives the block a hash under the difficulty target.
Prove
A Merkle tree ties every transaction to the block header, so one receipt can be proven without revealing the others.
Sync
Nodes share transactions and blocks over HTTP and each validates everything independently.
Resolve
If two versions of the chain exist, nodes follow the valid one with the most accumulated proof-of-work.
An honest note. I run all the nodes myself, so this chain is not decentralized. What it gives you today is tamper-evidence: a receipt, or any block, cannot be edited without the change being detected. It becomes stronger if independent nodes join, or if the latest block hash is anchored to a public network.