A Layer 2 scaling technique that executes transactions off-chain, bundles them, and posts compressed data back to L1. Optimistic rollups assume transactions are valid and use fraud proofs for disputes (7-day challenge period). ZK rollups generate cryptographic validity proofs for every batch. Rollups inherit L1 security while providing 10-100x throughput improvement.
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A Layer 2 scaling technique that executes transactions off-chain, bundles them, and posts compressed data back to L1. Optimistic rollups assume transactions are valid and use fraud proofs for disputes (7-day challenge period). ZK rollups generate cryptographic validity proofs for every batch. Rollups inherit L1 security while providing 10-100x throughput improvement.
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Rollup (rollup) Category: Blockchain General Definition: A Layer 2 scaling technique that executes transactions off-chain, bundles them, and posts compressed data back to L1. Optimistic rollups assume transactions are valid and use fraud proofs for disputes (7-day challenge period). ZK rollups generate cryptographic validity proofs for every batch. Rollups inherit L1 security while providing 10-100x throughput improvement. Related: Layer 2 (L2), Zero-Knowledge Proofs (ZKP)
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A scaling solution built on top of a Layer 1 blockchain that processes transactions off-chain while inheriting the security of the base layer. L2 types include optimistic rollups (Arbitrum, Optimism), ZK rollups (zkSync, StarkNet), state channels, and sidechains. L2s post transaction data or proofs back to L1 for finality.
A zero-knowledge proof is a cryptographic protocol by which a prover convinces a verifier that a statement is true — for example, that a state transition is valid — without revealing any information beyond the truth of the statement itself, satisfying the properties of completeness, soundness, and zero-knowledge. In Solana's ecosystem, ZKPs are used by ZK Compression (via Groth16 SNARKs) to prove correct state transitions for compressed accounts without storing full account state on-chain, and by the Token-2022 Confidential Transfers extension (via ElGamal encryption and range proofs) to prove token balances are non-negative without revealing the actual amounts. Solana's BPF VM exposes the alt_bn128 elliptic curve syscall to make on-chain Groth16 proof verification computationally feasible within the 1.4M compute unit budget.
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A rollup whose transaction sequencing is driven by the Layer 1 base chain's proposers rather than a dedicated centralized sequencer. L1 proposers permissionlessly include rollup blocks as part of L1 blocks, inheriting Ethereum's censorship resistance, liveness, and decentralization. The trade-off is higher latency (constrained by L1 block times), addressed through preconfirmation mechanisms.
A Bitcoin fungible token protocol created by Casey Rodarmor that launched at block 840,000 on April 20, 2024, coinciding with the fourth Bitcoin halving. Unlike BRC-20, Runes is UTXO-native, using OP_RETURN to store token data directly in transaction outputs without creating junk UTXOs. The protocol allows multiple token transfers in a single transaction and briefly accounted for over 80% of Bitcoin transactions in its first days.
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A scaling solution built on top of a Layer 1 blockchain that processes transactions off-chain while inheriting the security of the base layer. L2 types include optimistic rollups (Arbitrum, Optimism), ZK rollups (zkSync, StarkNet), state channels, and sidechains. L2s post transaction data or proofs back to L1 for finality.
A zero-knowledge proof is a cryptographic protocol by which a prover convinces a verifier that a statement is true — for example, that a state transition is valid — without revealing any information beyond the truth of the statement itself, satisfying the properties of completeness, soundness, and zero-knowledge. In Solana's ecosystem, ZKPs are used by ZK Compression (via Groth16 SNARKs) to prove correct state transitions for compressed accounts without storing full account state on-chain, and by the Token-2022 Confidential Transfers extension (via ElGamal encryption and range proofs) to prove token balances are non-negative without revealing the actual amounts. Solana's BPF VM exposes the alt_bn128 elliptic curve syscall to make on-chain Groth16 proof verification computationally feasible within the 1.4M compute unit budget.
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A distributed, append-only ledger that records transactions in cryptographically linked blocks. Each block contains a hash of the previous block, forming an immutable chain. Nodes in the network maintain copies of the ledger and reach agreement through consensus mechanisms. Blockchains enable trustless, decentralized record-keeping without a central authority.
The protocol by which nodes in a distributed network agree on the current state of the ledger. Common mechanisms include Proof of Work (Bitcoin), Proof of Stake (Ethereum, Solana), and BFT variants. Consensus ensures all honest nodes converge on the same transaction history despite potential network delays or malicious actors.
A consensus mechanism where validators are selected to produce blocks based on the amount of cryptocurrency they have staked (locked) as collateral. PoS is energy-efficient compared to Proof of Work. Misbehaving validators risk losing their stake (slashing). Solana, Ethereum (post-Merge), Cosmos, and Cardano use PoS variants.
A consensus mechanism where miners compete to solve computationally expensive puzzles to produce blocks and earn rewards. PoW provides strong security (51% attack resistance) but is energy-intensive. Bitcoin and pre-Merge Ethereum use PoW. The difficulty adjusts to maintain target block times regardless of total network hash power.