A binary tree where each leaf node is a hash of data and each internal node is the hash of its two children. The root hash (Merkle root) uniquely represents all underlying data. Merkle trees enable efficient proof of inclusion—proving a specific element exists requires only O(log n) hashes. Used in blockchains for transaction verification and state storage.
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A binary tree where each leaf node is a hash of data and each internal node is the hash of its two children. The root hash (Merkle root) uniquely represents all underlying data. Merkle trees enable efficient proof of inclusion—proving a specific element exists requires only O(log n) hashes. Used in blockchains for transaction verification and state storage.
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Merkle Tree (merkle-tree-general) Category: Blockchain General Definition: A binary tree where each leaf node is a hash of data and each internal node is the hash of its two children. The root hash (Merkle root) uniquely represents all underlying data. Merkle trees enable efficient proof of inclusion—proving a specific element exists requires only O(log n) hashes. Used in blockchains for transaction verification and state storage. Aliases: Hash Tree Related: Hash Function (Cryptographic), Merkle Proof
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A one-way mathematical function that maps arbitrary-length input to a fixed-size output (digest). Properties: deterministic, fast to compute, infeasible to reverse, collision-resistant. SHA-256 (used in Bitcoin, Solana PoH) produces 256-bit hashes. Keccak-256 is used in Ethereum. Hashes are used for block linking, Merkle trees, and data integrity.
A Merkle proof is the minimal set of sibling node hashes (the proof path) along the branch from a specific leaf to the tree root, allowing anyone to independently verify that a given leaf is part of a Merkle tree by recomputing the root from the leaf hash and the sibling hashes without needing any other tree data. In Solana's state compression, every compressed account or compressed NFT interaction requires the caller to supply a valid Merkle proof; the on-chain program hashes the proof against the current root stored in the Concurrent Merkle Tree account to confirm inclusion before executing the state change. Proof size scales linearly with tree depth (e.g., a depth-20 tree requires up to 20 sibling hashes, each 32 bytes), so the canopy is used to pre-store upper-level nodes on-chain to reduce the proof data that must be passed in transactions.
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A one-way mathematical function that maps arbitrary-length input to a fixed-size output (digest). Properties: deterministic, fast to compute, infeasible to reverse, collision-resistant. SHA-256 (used in Bitcoin, Solana PoH) produces 256-bit hashes. Keccak-256 is used in Ethereum. Hashes are used for block linking, Merkle trees, and data integrity.
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A one-way mathematical function that maps arbitrary-length input to a fixed-size output (digest). Properties: deterministic, fast to compute, infeasible to reverse, collision-resistant. SHA-256 (used in Bitcoin, Solana PoH) produces 256-bit hashes. Keccak-256 is used in Ethereum. Hashes are used for block linking, Merkle trees, and data integrity.
A Merkle proof is the minimal set of sibling node hashes (the proof path) along the branch from a specific leaf to the tree root, allowing anyone to independently verify that a given leaf is part of a Merkle tree by recomputing the root from the leaf hash and the sibling hashes without needing any other tree data. In Solana's state compression, every compressed account or compressed NFT interaction requires the caller to supply a valid Merkle proof; the on-chain program hashes the proof against the current root stored in the Concurrent Merkle Tree account to confirm inclusion before executing the state change. Proof size scales linearly with tree depth (e.g., a depth-20 tree requires up to 20 sibling hashes, each 32 bytes), so the canopy is used to pre-store upper-level nodes on-chain to reduce the proof data that must be passed in transactions.
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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.