Glossary

A group of blockchains that can communicate with each other in a trust-minimized way.

The header of a block contains a list of relevant metadata.

A full node that is responsible for producing blocks.

The capacity of each block.

The ability for applications on a blockchain to read and write state to each other.

A function of modular blockchains where the ordering of transactions is agreed upon by a set of validators.

A consensus algorithm is a set of rules that blockchains use to determine how nodes produce new blocks and agree to finalize them.

A modular blockchain that provides transaction ordering for other modular blockchains, like rollups.

The Cosmos SDK is a development kit for building PoS layer 1 blockchains with Tendermint as the consensus mechanism.

The ability for separate blockchains to communicate and interact with each other.

DA stands for Data Availability.

DAC stands for Data Availability Committee.

DAS stands for Data Availability Sampling.

A technique in which nodes can verify that data is available for a block without having to download the entire block, formerly known as data availability proofs.

The condition of whether or not transaction data was made available for nodes to download, when a block was proposed.

A data availability committee (DAC) is a permissioned group of nodes responsible for providing data availability to a blockchain.

A blockchain that provides for other types of chains, like rollups.

A measurement of the data capacity of a blockchain. Data throughput is calculated by the amount of data that a blockchain can process, measured in kb/s or mb/s.

A type of attack that occurs when a block producer proposes a new block but does not share the underlying transaction data that was used to create the block.

The handling and resolution of disputes, commonly used as a term in relation to optimistic rollups and their fraud proof mechanism.

EE stands for Execution Environment.

A function of modular blockchains where transactions are executed and the new state of the chain is determined.

The virtual environment within a blockchain where transactions are processed, and accounts and smart contracts live.

A type of modular blockchain whose primary job is hosting smart contracts and executing transactions.

A type of market that blockchains implement to prevent malicious actors from spamming the network.

A software upgrade that causes the blockchain to split into two chains that may or may not be compatible with each other.

An algorithm that nodes use to correctly identify and follow the canonical chain.

A type of node that fully verifies a blockchain.

The assumption that a majority of blockchain participants (such as the validator set) are honest and follow the rules of the protocol.

The assumption that only a minority of blockchain participants are honest and follow the rules of the protocol.

Communication that occurs between blockchains that are in different clusters.

ISR stands for Intermediate State Root.

A type of node that only downloads and verifies block headers, relying on an honest majority assumption that the state of the chain indicated by the block header is valid.

In Celestia, a light node is a type of node that verifies block headers and does data availability sampling.

Liveness is a property of blockchains where validators produce new blocks and successfully finalize transactions.

A type of blockchain that specializes in one or two tasks, rather than all of them.

A combination of multiple modular blockchains.

A type of blockchain that performs all tasks by itself.

A Namespaced Merkle Tree (NMT) is a type of binary Merkle tree where each node in the tree is tagged by the minimum and maximum namespace of their children.

NMT stands for Namespaced Merkle Tree.

A node is a device that participates in a blockchain protocol by running its software.

Off-chain data availability occurs when an L2 publishes its transaction data somewhere separate from the L1 it settles on.

On-chain data availability occurs when an L2 publishes its transaction data to its designated L1.

A type of rollup that posts its blocks to a separate chain without any cryptographic proofs that attest to their validity.

ORU stands for Optimistic Rollup.

A network in which nodes are connected and can communicate directly with each other without reliance on a third party to facilitate communication.

PFB stands for PayforBlob.

Proof of Stake is a mechanism that requires blockchain participants to stake a token to participate in consensus.

QGB stands for Quantum Gravity Bridge.

A type of blockchain that posts their blocks to a separate chain to receive consensus and ensure data availability.

Safety is a property of blockchains that a chain will not fork.

Scalability is the ability of a blockchain to increase its capacity without an equal increase in the cost to run a node that verifies the chain.

A function of modular blockchains where transaction proofs from rollups are verified and disputes are resolved.

A modular blockchain whose primary role is to provide proof verification and dispute resolution for rollups.

A sequencer is a type of rollup node that is responsible for collecting transactions and producing new blocks.

The process of separating a blockchain from a single chain into multiple chains (shards).

Security that a blockchain inherits from an external source.

A mechanism employed in PoS blockchains that is used to deter and punish malicious behavior.

A smart contract is a program that runs on a blockchain.

The process by which individuals come to an agreement on a change that will be made to a blockchain.

An application that is deployed on its own sovereign blockchain.

A blockchain that has independent control over itself and its applications via social consensus.

A type of rollup that does not use a settlement layer to determine its canonical chain and validity rules.

A method for proving that a state transition is invalid.

An assumption that the network is synchronous such that when a message is sent it will be received within a certain amount of time.

A measurement of the capacity of a blockchain. Throughput primarily measures two elements: data throughput and transaction throughput.

A problem that is concerned with whether the data in the proposed block can be verified that it is available.

The computational capacity of a blockchain. Transaction throughput is commonly calculated by the number of transactions that can be processed per second (TPS).

A bridge between two blockchains that doesn’t require an intermediary, a committee, or an honest majority assumption to ensure that funds can’t be stolen.

A bridge between two blockchains that requires either a trusted intermediary, committee, or an honest majority assumption to ensure that funds can’t be stolen.

A full node that is part of the validator set in a PoS blockchain.

A group of validators that are responsible for directly participating in the consensus of a blockchain through either voting, producing, or proposing blocks.

A type of cryptographic proof that can be used to attest to the validity of a state transition.

A type of zero-knowledge rollup that posts its data off-chain rather than to its parent chain.

A zero-knowledge rollup with options for both on-chain and off-chain data availability.

A type of rollup that posts its blocks to a separate chain with a validity proof that attests to the correctness of the block.

ZKR stands for ZK Rollup.