unspent transaction output (UTXO) [English]
- Abbr: UTXO
No definition in earlier IP projects. ITrust definition not yet developed.
- Bitcoin Developer Glossary 2017 (†791 s.v. "UTXO"): An Unspent Transaction Output (UTXO) that can be spent as an input in a new transaction. Not To Be Confused With · Output (any output, whether spent or not. Outputs are a superset of UTXOs)
- Chain Documentation 2017 (†840 ): Each new transaction in the blockchain consumes some unspent outputs and creates others. An output is considered unspent when it has not yet been used as an input to a new transaction. All asset units on a blockchain exist in the unspent output set.
- Scaling Bitcoin  (†845 s.v. "UTXO (Unspent Transaction Output)"): An Unspent Transaction Output (UTXO) that can be spent as an input in a new transaction.
- Seibold et al. 2016 (†821 p.19): An unspent transaction model, in which assets are passed directly from one transaction's outputs to the next one's inputs and each output can only be spent once.
- Buterin  (†818 s.v. "Scripting" ): Even without any extensions, the Bitcoin protocol actually does facilitate a weak version of a concept of "smart contracts". UTXO in Bitcoin can be owned not just by a public key, but also by a more complicated script expressed in a simple stack-based programming language. In this paradigm, a transaction spending that UTXO must provide data that satisfies the script. Indeed, even the basic public key ownership mechanism is implemented via a script: the script takes an elliptic curve signature as input, verifies it against the transaction and the address that owns the UTXO, and returns 1 if the verification is successful and 0 otherwise. (†2346)