design-document series

Bitcoin architecture evolution — Satoshi era v0.1 vs modern v27+ baseline

Cross-cutting architecture comparison across every subsystem: Satoshi's v0.1 (January 2009) side by side with modern Bitcoin Core v27+, with split diagrams and domain tables.

Bitcoin block and chain design — headers, Merkle trees, and chain selection

How Bitcoin blocks are structured, how Merkle trees commit transactions to block headers, and how the most-work chain selection rule resolves forks.

Bitcoin ecosystem design — Lightning Network, sidechains, and L1 extensions

How the Bitcoin ecosystem layers above and around the base chain: Lightning payment channels, federated sidechains, L1 envelope extensions, and mining pool architectures.

Bitcoin consensus design — proof of work, difficulty adjustment, and fork handling

How Bitcoin nodes agree on a single chain: SHA-256d proof of work, the difficulty adjustment algorithm, block validation rules, fork resolution, and probabilistic finality.

Bitcoin cryptography design — keys, signatures, hashes, and address derivation

How Bitcoin uses elliptic-curve keys, digital signatures, hash functions, and deterministic derivation to secure ownership without trusted third parties.

Bitcoin monetary design — issuance schedule, fee market, and incentive structure

How Bitcoin's 21 million cap emerges from a geometric halving series, how block rewards transition from subsidy to fees, and how the incentive model sustains honest mining.

Bitcoin P2P network design — node discovery, message relay, and block propagation

How Bitcoin nodes find each other, exchange transactions and blocks, and resist network-level attacks across the P2P gossip layer.

Bitcoin transaction design — UTXO model, Script, and signature schemes

Deep-dive into Bitcoin's transaction layer: UTXO lifecycle, transaction structure, Script evaluation, ECDSA and Schnorr signatures, SegWit, and Taproot.

Bitcoin wallet and interface design — key management, transaction construction, and RPC

How Bitcoin Core manages keys, constructs transactions, selects coins, estimates fees, and exposes functionality through RPC, REST, and ZMQ interfaces.

Bitcoin security model — attack surfaces, trust assumptions, and defense layers

Bitcoin's threat model mapped end-to-end: what the protocol trusts, what it defends against, how each attack is countered, and where open risks remain.

Bitcoin storage design — block database, UTXO set, and chain state management

How Bitcoin Core persists blocks, maintains the UTXO set, indexes chain state, manages the mempool, prunes historical data, and bootstraps via assumeUTXO.