Blockchains and infrastructure
Last reviewed November 1, 2026
Behind every coin is a network with its own rules. Some are fast, some put security first, and none manages both without trade-offs.
People in the industry talk about the blockchain trilemma: a network wants to be secure, decentralised and fast, but can only fully deliver two of the three. Every chain picks a different balance.
For you, the chain a transaction runs on decides what it costs, how quickly it settles, and how many operators you have to trust.
Layer 1
Layer 1 means an independent blockchain with its own consensus: Bitcoin, Ethereum, Solana, Cardano, Avalanche and others. Solana, for example, relies on very powerful machines to reach high speed, which limits who can afford to run a validator.
Layer 2 and rollups
Layer 2 networks run on top of a base chain and borrow its security. Optimistic rollups such as Arbitrum and Optimism assume transactions are valid and allow a challenge window. ZK rollups prove every state change with a cryptographic proof. Many rollups still depend on a single operator, which is a real risk.
Oracles
A blockchain only knows its own data. For a smart contract to learn the price of the pound in dollars, it needs an oracle to bring that data in. Chainlink is the best known. Faulty oracle prices have caused multi-million-dollar losses in DeFi.
Bridges
Bridges move value between chains: the asset is locked on one side and a representation is issued on the other. Because they hold large sums, bridges are favourite targets for hackers. The 2022 Ronin bridge attack took about $600 million.