Blockchain
Shared blockchain primitives plus per-chain concepts, so the differences between chains fall out of the graph.
What this bundle is
A curated, cross-linked knowledge base for understanding the most important blockchains together, not in isolation. The design principle: the ideas every chain shares live once as chain-agnostic primitives, and each chain describes only its own choices, linking back to the primitive it implements. The result is that "where and why the chains differ" is visible in the graph itself.
How to read it
- Shared concepts. The primitives every chain builds on: hashing, signatures, Merkle trees, blocks, transactions, consensus with proof of work and proof of stake, the UTXO and account models, mempool, finality, forks, smart contracts, gas and fees, nodes, the native token, and the scalability trilemma.
- Per-chain concepts. Bitcoin, Ethereum, and Cardano, each a folder of specific choices linking back to the shared primitives.
- Comparisons. The payoff: UTXO vs account, proof of work vs proof of stake, and the overall design philosophy.
The one-line contrast
Bitcoin is minimalist sound money; Ethereum is a programmable world computer; Cardano is a research-first chain that keeps Bitcoin's UTXO lineage while adding Ethereum-style programmability under a different proof-of-stake design. Almost every technical difference is downstream of these stances, as design philosophy draws out. The bundle is built to extend: adding a chain means adding a folder that links into the same shared primitives.
A note on accuracy
Technical facts are cited to primary sources (the Bitcoin whitepaper and BIPs, ethereum.org and the EIPs). Fast-moving or demand-dependent values (Ethereum's net issuance, roadmap dates) are flagged as such rather than asserted as constants.
What's inside
Concepts
- Cryptographic hash function
A one-way function mapping arbitrary data to a fixed-size digest, the workhorse primitive of every blockchain.
- Public-key cryptography and digital signatures
Keypairs and signatures let a holder prove ownership and authorize transactions without revealing the secret key.
- Merkle tree
A hash tree that summarizes many transactions into one root, enabling compact proofs of inclusion.
- Block and the blockchain
A batch of transactions cryptographically chained to its predecessor, forming an append-only ledger.
- What it is
- Distributed consensus
How mutually distrusting nodes agree on one ordered history without a central authority.
- What it is
- What it is
- Finality
The guarantee that a confirmed transaction cannot be reversed, either probabilistic or economic.
- UTXO model
A ledger of discrete unspent coins consumed and recreated by each transaction, with no protocol-level balances.
- Account model
A global state of balances that transactions mutate directly, the natural fit for stateful smart contracts.
- Smart contract
Code deployed to the chain that executes deterministically when called, enabling programmable money.
- Gas and transaction fees
The pricing of scarce block space and computation, which funds security and resists spam.
- Native token and monetary policy
The chain's built-in asset that pays for security and fees, governed by a protocol-defined issuance schedule.
- Mempool
The pool of validated but unconfirmed transactions waiting to be included in a block.
- Node
A participant that stores the chain and independently validates every rule, the basis of decentralization.
- Forks
Divergences in the chain or its rules, from momentary reorgs to permanent protocol splits.
- The scalability trilemma
The claim that a blockchain struggles to maximize decentralization, security, and scalability at once.
Bitcoin
- What Bitcoin is
- How mining works
- Bitcoin monetary policy
A hard ~21 million cap issued via a block subsidy that halves every 210,000 blocks until ~2140.
- Bitcoin UTXO transactions
How Bitcoin transactions consume prior outputs and create new ones, with change and implicit fees.
- Bitcoin Script
A stack-based, intentionally non-Turing-complete language for expressing spending conditions.
- Upgrade culture: soft forks
- Lightning Network
Bitcoin's layer-2 scaling via bidirectional off-chain payment channels settled on the base chain.
Cardano
- Cardano
A research-first proof-of-stake blockchain that extends the UTXO model to smart contracts via EUTXO.
- What it is
- The third accounting model
- Cardano native tokens
A multi-asset ledger where custom tokens are first-class citizens, minted without a smart contract.
- Plutus and Cardano smart contracts
Haskell-based on-chain scripts that validate spending in the EUTXO model, with Marlowe and newer languages.
- ADA monetary policy
A 45 billion ADA cap funded from a diminishing reserve that also feeds staking rewards and a treasury.
- The hard fork combinator
Cardano's mechanism for upgrading via hard forks without a chain split or disruption.
- On-chain governance by CIP-1694
- Cardano hard fork history
Every activated Cardano hard fork from Byron (2017) to van Rossem (June 2026), with dates and headline features.
Comparison
- UTXO vs account model
How Bitcoin's coin-based ledger and Ethereum's balance-based state lead to different capabilities.
- Proof of work vs proof of stake
How Bitcoin's energy-based and Ethereum's capital-based consensus differ in cost, finality, and risk.
- Bitcoin vs Ethereum design philosophy
Sound money and minimalism versus a programmable, evolving world computer, and why their choices cohere.
Ethereum
- Ethereum
A programmable blockchain, the "world computer," running smart contracts under proof of stake.
- The Ethereum Virtual Machine (EVM)
A Turing-complete, deterministic state machine that executes smart-contract bytecode on every node.
- Ethereum accounts and state
Externally owned and contract accounts over a global state, Ethereum's alternative to Bitcoin's UTXOs.
- Ethereum gas and EIP-1559
Metered computation priced in gas, with a burned base fee plus a priority tip since the London upgrade.
- The Merge
- Ether monetary policy
An uncapped supply set by validator issuance minus the EIP-1559 burn, the "ultrasound money" framing.
- Scale off-chain, secure on-chain