Proof of Reserves
An attestation that a custodian holds at least as much of an asset as it owes to customers. Modern PoR uses a Merkle tree…
Glossary
Glossary — crypto terms, defined
80 articles · refreshed Jun 10, 2026
Private key
A secret cryptographic key that proves ownership of cryptocurrency at a specific address. Anyone with the private key can spend the funds. Private keys…
POS
Proof-of-Stake — consensus mechanism where validators stake tokens that can be slashed for misbehavior. Validators are selected to propose blocks proportionally to their stake.…
POW
Proof-of-Work — consensus mechanism where validators (miners) expend computational work to add blocks. Bitcoin uses PoW; Ethereum used PoW until September 2022. PoW provides…
Oracle
A service that brings off-chain data (price feeds, weather, sports results) on-chain for smart contracts to consume. Chainlink is the largest oracle network. Oracles…
On-chain
Recorded on the public blockchain ledger. Contrasts with "off-chain" (recorded by an exchange or other intermediary, not visible on-chain). On-chain analytics — measuring wallet…
Nakamoto coefficient
The minimum number of independent validators or pools required to halt a blockchain. For proof-of-stake chains, this means controlling 33%+ of staked supply. Bitcoin…
NFT
Non-Fungible Token — a token whose individual units are distinguishable, unlike fungible tokens (where each USDC is identical to every other USDC). NFTs are…
MEV
Maximal Extractable Value — value miners or validators can extract by reordering, including, or excluding transactions in a block. Common forms include front-running, sandwich…
Mining
The process of validating proof-of-work blocks by expending computational energy to solve cryptographic puzzles. Miners are rewarded in block subsidy + transaction fees. Bitcoin…