Are all UTXOs locked by an address spent in a transaction?
Imagine I have 2 UTXOs locked by my address, each of which allows me to spend 5 bitcoins.
If I subsequently want to send just 2 bitcoins to someone else, will both UTXOs be used as inputs in the transaction, where I now receive 8 BTC change as a single UTXO locked to my address, or as the value I want to spend can be covered by a single UTXO, is only one of the 5 BTC UTXOs spent by the transaction and I receive change in a new UTXO worth 3 BTC locked by my address. So now my address locks two UTXOs, one for 5 BTC which was not needed in this transaction, plus the change I just received for 3 BTC. Or something else?
utxo transaction-input address-reuse coin-selection
edited 2 hours ago
Murch♦
35.3k27115330
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
Imagine I have 2 UTXOs locked by my address, each of which allows me to spend 5 bitcoins.
If I subsequently want to send just 2 bitcoins to someone else, will both UTXOs be used as inputs in the transaction, where I now receive 8 BTC change as a single UTXO locked to my address, or as the value I want to spend can be covered by a single UTXO, is only one of the 5 BTC UTXOs spent by the transaction and I receive change in a new UTXO worth 3 BTC locked by my address. So now my address locks two UTXOs, one for 5 BTC which was not needed in this transaction, plus the change I just received for 3 BTC. Or something else?
utxo transaction-input address-reuse coin-selection
edited 2 hours ago
Murch♦
35.3k27115330
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
As an aside, this question helps exemplify why address reuse is very bad for privacy: the person you pay 2 BTC to will be able to see that you control an address that holds many UTXOs, rather than just seeing the single UTXO that you spent to pay them. So with address reuse, you grant anyone you transact with the ability to see a much larger portion of your financial history.
– chytrik
1 hour ago
add a comment |
Imagine I have 2 UTXOs locked by my address, each of which allows me to spend 5 bitcoins.
If I subsequently want to send just 2 bitcoins to someone else, will both UTXOs be used as inputs in the transaction, where I now receive 8 BTC change as a single UTXO locked to my address, or as the value I want to spend can be covered by a single UTXO, is only one of the 5 BTC UTXOs spent by the transaction and I receive change in a new UTXO worth 3 BTC locked by my address. So now my address locks two UTXOs, one for 5 BTC which was not needed in this transaction, plus the change I just received for 3 BTC. Or something else?
utxo transaction-input address-reuse coin-selection
edited 2 hours ago
Murch♦
35.3k27115330
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Imagine I have 2 UTXOs locked by my address, each of which allows me to spend 5 bitcoins.
If I subsequently want to send just 2 bitcoins to someone else, will both UTXOs be used as inputs in the transaction, where I now receive 8 BTC change as a single UTXO locked to my address, or as the value I want to spend can be covered by a single UTXO, is only one of the 5 BTC UTXOs spent by the transaction and I receive change in a new UTXO worth 3 BTC locked by my address. So now my address locks two UTXOs, one for 5 BTC which was not needed in this transaction, plus the change I just received for 3 BTC. Or something else?
utxo transaction-input address-reuse coin-selection
utxo transaction-input address-reuse coin-selection
edited 2 hours ago
Murch♦
35.3k27115330
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
Murch♦
35.3k27115330
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
Murch♦
35.3k27115330
edited 2 hours ago
Murch♦
35.3k27115330
edited 2 hours ago
Murch♦
35.3k27115330
35.3k27115330
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
asked 3 hours ago
Simon O'HanlonSimon O'Hanlon
1184
1184
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Simon O'Hanlon is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
As an aside, this question helps exemplify why address reuse is very bad for privacy: the person you pay 2 BTC to will be able to see that you control an address that holds many UTXOs, rather than just seeing the single UTXO that you spent to pay them. So with address reuse, you grant anyone you transact with the ability to see a much larger portion of your financial history.
– chytrik
1 hour ago
add a comment |
As an aside, this question helps exemplify why address reuse is very bad for privacy: the person you pay 2 BTC to will be able to see that you control an address that holds many UTXOs, rather than just seeing the single UTXO that you spent to pay them. So with address reuse, you grant anyone you transact with the ability to see a much larger portion of your financial history.
– chytrik
1 hour ago
As an aside, this question helps exemplify why address reuse is very bad for privacy: the person you pay 2 BTC to will be able to see that you control an address that holds many UTXOs, rather than just seeing the single UTXO that you spent to pay them. So with address reuse, you grant anyone you transact with the ability to see a much larger portion of your financial history.
– chytrik
1 hour ago
As an aside, this question helps exemplify why address reuse is very bad for privacy: the person you pay 2 BTC to will be able to see that you control an address that holds many UTXOs, rather than just seeing the single UTXO that you spent to pay them. So with address reuse, you grant anyone you transact with the ability to see a much larger portion of your financial history.
– chytrik
1 hour ago
add a comment |
1 Answer
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Transactions explicitly refer to which UTXOs they are spending.
You can construct a transaction which only spends one of the two 5-BTC UTXOs, and sends 2 BTC to the destination and 3 BTC to a (possibly new) address of yourself.
You can also construct a transaction which spends both, and sends 8 BTC back to yourself. Or it could have multiple outputs that send funds back to yourself, summing up to 8 BTC.
In short: there is nothing special about the two UTXOs that share an address, apart from the fact that the same key can sign for both - but it doesn't have to.
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
add a comment |
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1 Answer
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votes
Transactions explicitly refer to which UTXOs they are spending.
You can construct a transaction which only spends one of the two 5-BTC UTXOs, and sends 2 BTC to the destination and 3 BTC to a (possibly new) address of yourself.
You can also construct a transaction which spends both, and sends 8 BTC back to yourself. Or it could have multiple outputs that send funds back to yourself, summing up to 8 BTC.
In short: there is nothing special about the two UTXOs that share an address, apart from the fact that the same key can sign for both - but it doesn't have to.
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
add a comment |
Transactions explicitly refer to which UTXOs they are spending.
You can construct a transaction which only spends one of the two 5-BTC UTXOs, and sends 2 BTC to the destination and 3 BTC to a (possibly new) address of yourself.
You can also construct a transaction which spends both, and sends 8 BTC back to yourself. Or it could have multiple outputs that send funds back to yourself, summing up to 8 BTC.
In short: there is nothing special about the two UTXOs that share an address, apart from the fact that the same key can sign for both - but it doesn't have to.
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
add a comment |
Transactions explicitly refer to which UTXOs they are spending.
You can construct a transaction which only spends one of the two 5-BTC UTXOs, and sends 2 BTC to the destination and 3 BTC to a (possibly new) address of yourself.
You can also construct a transaction which spends both, and sends 8 BTC back to yourself. Or it could have multiple outputs that send funds back to yourself, summing up to 8 BTC.
In short: there is nothing special about the two UTXOs that share an address, apart from the fact that the same key can sign for both - but it doesn't have to.
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
Transactions explicitly refer to which UTXOs they are spending.
You can construct a transaction which only spends one of the two 5-BTC UTXOs, and sends 2 BTC to the destination and 3 BTC to a (possibly new) address of yourself.
You can also construct a transaction which spends both, and sends 8 BTC back to yourself. Or it could have multiple outputs that send funds back to yourself, summing up to 8 BTC.
In short: there is nothing special about the two UTXOs that share an address, apart from the fact that the same key can sign for both - but it doesn't have to.
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
answered 2 hours ago
Pieter WuillePieter Wuille
47.2k399158
47.2k399158
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
add a comment |
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
Thank you for this clear explanation of the wonderful flexibility of the UTXO model.
– Simon O'Hanlon
2 hours ago
add a comment |
Simon O'Hanlon is a new contributor. Be nice, and check out our Code of Conduct.
Simon O'Hanlon is a new contributor. Be nice, and check out our Code of Conduct.
Simon O'Hanlon is a new contributor. Be nice, and check out our Code of Conduct.
Simon O'Hanlon is a new contributor. Be nice, and check out our Code of Conduct.
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As an aside, this question helps exemplify why address reuse is very bad for privacy: the person you pay 2 BTC to will be able to see that you control an address that holds many UTXOs, rather than just seeing the single UTXO that you spent to pay them. So with address reuse, you grant anyone you transact with the ability to see a much larger portion of your financial history.
– chytrik
1 hour ago