Bitcoin UTXOs: Transaction Inputs, Change, and Wallet Balances
Summary
The document introduces Bitcoin's unspent transaction output model and contrasts it with account-based balance tracking. A wallet's spendable funds consist of previously created outputs. To make a payment, it selects one or more outputs as inputs, consumes them in full, and creates new outputs for the recipient and any change returned to the sender. Summing a wallet's unspent outputs gives its balance, while transaction scripts set conditions for spending them.
It also outlines transaction components, explains how outputs prevent double spending, and discusses coinbase outputs, wallet indexing, and small leftover amounts known as dust. Dusting attacks use tiny outputs to try to link addresses and identify potential targets; the text says these do not by themselves grant access to funds. The article is an introductory protocol explanation rather than trading research, and its cash analogy is simplified. It provides no market strategy, investment evidence, or analysis of UTXO-based trading behavior.
Key ideas
- A Bitcoin wallet balance is the sum of its unspent transaction outputs.
- Spending an output consumes it and creates new outputs, including possible change.
- Transaction scripts specify conditions for spending outputs, typically using proof of key control.
- Dust consists of very small outputs that may cost more to spend than their value.
- Dusting can help link addresses, but the document says it does not give attackers control of funds.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.