What order does Bitcoin core place the inputs it spends in? Is it random? Is it sorted by anything? What, if anything, can you tell about the originator of a transaction by the input ordering?


1 Answer 1


The inputs are chosen by the function SelectCoins() in CreateTransaction() and then added one by one (without shuffling) to the transaction.

The order is defined by the coin selection (CWallet::SelectCoinsMinConf) which does a random shuffle of the potential useful inputs and a stochastic approximation.

Mind also that Bitcoin-Core's coin selection could be improved and there are several issues and improve proposals ([1], [2], [3])

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