Input

In the context of blockchain, "input" might sound like a technical term, but it’s really just about tracking where your digital money is coming from when you make a transaction. Each input represents a portion of cryptocurrency that hasn’t been spent yet, known as an unspent transaction output (UTXO), from a previous transaction. When you send cryptocurrency, your wallet will gather these inputs—kind of like picking out specific bills from your wallet to pay for something. The total value of these inputs must at least match the amount you want to send, plus any transaction fees.

For example, if you have three separate UTXOs from previous transactions, each worth a different amount, your wallet might combine them to make up the total you need for a new transaction. Any excess beyond what’s needed to cover the transaction and fees is returned to you as change, in the form of a new UTXO. This way, the blockchain can keep track of every fraction of cryptocurrency, ensuring that nothing gets lost or double-spent. It’s a bit like keeping an exact ledger of every penny you spend, with each input and output carefully recorded.

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