UTXO (Unspent Transaction Output)
Definition
The fundamental accounting unit of the Bitcoin protocol. Each transaction consumes previous UTXOs as inputs and creates new UTXOs as outputs. The complete spending history of any coin is traceable through the UTXO graph from its creation in a coinbase transaction.
Related terms
- Account Model
- Ethereum's approach, where each address holds a running balance incremented or decremented by transactions. Simpler to reason about but less transparent about...
- Address Clustering
- A technique that groups blockchain addresses likely controlled by the same entity. The most common method uses the common-input-ownership heuristic: all input...
- Block Confirmation
- The count of blocks added to the chain after the block containing a specific transaction. Higher confirmation counts mean greater computational cost...
- Blockchain Explorer
- A web interface or API that indexes a blockchain and allows queries by address, transaction hash, or block. Examples: Blockstream.info for Bitcoin,...
- Distributed Ledger
- A transaction record replicated across many independent nodes. Each node holds a full or partial copy and validates new entries against the...
- KYC (Know Your Customer)
- The identity verification process that regulated exchanges and virtual asset service providers (VASPs) are legally required to perform before allowing users to...
- Mixer / Tumbler
- A service that pools cryptocurrency from multiple users, exchanges it, and returns equivalent amounts to different addresses, intentionally breaking the transaction graph....
- Private (Permissioned) Blockchain
- A network where participation is restricted to known, approved nodes. Used by banks and supply chains for transaction settlement. Records are not...
- Public Blockchain
- A permissionless network where anyone can read the ledger, submit transactions, or run a node. Bitcoin and Ethereum are public. The ledger...
- VASP (Virtual Asset Service Provider)
- The Financial Action Task Force (FATF) term for businesses that exchange, transfer, or custody cryptocurrency on behalf of customers. VASPs are subject...
Explained in these topics
- Blockchain Fundamentals for InvestigatorsBitcoin's accounting unit. Each UTXO is a discrete chunk of value from a prior transaction's output. Spending it consumes it entirely; change comes back as a n...
- Cryptocurrency Tracing and Blockchain AnalysisThe fundamental accounting unit of the Bitcoin protocol. Each transaction consumes previous UTXOs as inputs and creates new UTXOs as outputs. The complete spen...