I know that bitcoin transaction is based on UTXO, including input script and output script. But recently I browse bitcoin explorer and I found it listed source addresses of a transaction. I wonder whether the source address it listed is the one in the last transaction's output script also working as the input script of this transaction?

1 Answer 1


Yes, source address is the locking bytecode of a "prevout" (output of an ancestor transaction) being consumed as a transaction input. Because any transaction can have multiple inputs, then any existing UTXO can have multiple source addresses.

Any UTXOs full ancestry could be constructed as a directed acyclic graph (DAG) where the UTXO would be at the root of the graph, and each end would trace to some coinbase output. Most UTXOs would trace back to lots and lots of coinbase outputs with each output being a distinct endpoint.

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    Get it. Thank you very much!
    – Harry
    Oct 11, 2023 at 6:29
  • I didn't mean to say that, maybe I should reword. Each endpoint of the DAG would be 1 coinbase UTXO but there would be many such endpoints. Most UTXOs would trace back to lots and lots of coinbase outputs. If they were mixed, the graph would get quite big. Oct 11, 2023 at 9:16
  • Thanks for clarifying. Oct 11, 2023 at 12:14
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    Note that the “source addresses” should not be confused with a “from address”: just because funds were previously under some specific output script’s control, does not necessarily mean that the sender will receive funds sent to that script. For example when a transaction is sent by a custodial wallet service, the “source address” may be associated with a different customer of the custodian than the sender.
    – Murch
    Oct 11, 2023 at 18:12

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