What is 'spent' and 'unspent' ?
Bitcoin, a decentralized digital currency, relies on blockchain technology to facilitate and verify transactions. In the context of Bitcoin, the terms ‘spent’ and ‘unspent’ refer to the status of transaction outputs (UTXOs) associated with a specific Bitcoin address.
‘Spent’ refers to the condition in which a UTXO has been used as an input for a Bitcoin transaction. When a transaction occurs, the sender selects the UTXO as the input, and the associated Bitcoin value is sent to the recipient's address. Once spent, the UTXO cannot be reused for future transactions. This is crucial to prevent double spending within the Bitcoin network and ensure transaction integrity.
On the other hand, ‘unspent’ means that a UTXO has never been used as an input in any transaction. Unspent UTXOs retain their value and can be used as inputs for future transactions. These UTXOs are recorded in a database called the UTXO set, which stores ownership and current balance information for each Bitcoin address.
What is the role of UTXO (Unspent Transaction Output)?
The UTXO-Set plays a crucial role in verifying the validity of new transactions, preventing double spending, and maintaining security across the Bitcoin network. By examining the UTXO-Set, the available balance for a specific Bitcoin address can be determined.
In Bitcoin, UTXOs act as the building blocks of transactions. When a transaction occurs, the UTXOs used as inputs are consumed, and new unspent UTXOs are generated as outputs. Over time, the UTXO trail forms an immutable chain of transactions within the blockchain, validating every transaction that occurs.
Spent dan unspent Illustration
‘Spent transaction’ as explained before is when the digital assets that we send to another address have been successfully input to another bitcoin transaction, or we could say the bitcoin has already been re-send to another address. Otherwise, an ‘unspent transaction’ means that the bitcoin that we send to another address has not become an input to any other transaction.