Glossary
Blockchain Trilemma
The idea that a blockchain struggles to maximize decentralization, security, and scalability all at once, so improving one usually forces a trade-off against another.
The blockchain trilemma, a framing popularized by Vitalik Buterin, holds that a network can comfortably optimize for only two of three properties at any given time: decentralization, security, and scalability. Pushing throughput up by adding bigger blocks or fewer validators, for example, tends to weaken decentralization or the security guarantees that come with a wide validator set.
Most modern scaling research is an attempt to break the trilemma rather than accept it. Rollups, sharding, and data availability sampling try to raise throughput while keeping the base layer decentralized and secure, letting ordinary users verify the chain without trusting a handful of powerful nodes.