Unspent Transaction Output (UTXO)
A discrete spendable output on a UTXO blockchain, similar to a digital coin that must be spent whole.
- Acronym
- UTXO
- Also known as
- UTXO
An unspent transaction output (UTXO) is a chunk of value created by a transaction and not yet consumed by a later transaction. Wallet balances on UTXO chains are the sum of spendable outputs controlled by the user's keys.
UTXO systems track coins rather than account balances. Every valid transaction consumes existing outputs as inputs and creates new outputs with locking conditions for future spending.
UTXO selection affects fees and privacy. Spending many small outputs increases transaction size, while combining unrelated outputs can reveal that the same wallet likely controls them.
Related terms
6 linkedExplore connected entries beyond the alphabetical index.
Transaction
→A signed data message that asks a blockchain to transfer value, execute code, or update state.
Block
→A batch of valid transactions added to a blockchain, linked to the previous block by a cryptographic hash.
Bitcoin (BTC)
→The first widely adopted cryptocurrency, using proof of work and a fixed 21 million coin supply.
P2PKH
→A common script type where the output can be spent by proving knowledge of the private key corresponding to a hashed public key.
P2SH
→A script type where the output is locked to the hash of a redeem script, enabling features like multi-sig.
Opcode
→A fundamental element of Bitcoin's scripting language that enables complex transactions.
All terms and definitions may update as the Cryptionary improves.
