4 ms·

>Unlike physical goods which can only exist in one place at one time, it is conceivable that with a powerful enough computer, the solution could be found entire

>Unlike physical goods which can only exist in one place at one time, it is conceivable that with a powerful enough computer, the solution could be found entirely honestly by a third party simply doing some math and stumbling upon the answer at random, or by asking the right questions and exploiting some as-yet-undiscovered weakness in the implementation. This seems fanciful, but there are in fact UTXOs which could be "owned" by multiple people without explicitly sharing the key. For example, Peter Todd created an UTXO that you spend by proving that a sha1 collision (any collision) exists [1]. Two parties could thus acquire ownership independently. [1] https://bitcointalk.org/index.php?topic=293382.0 https://bitcointalk.org/index.php?topic=293382.0

PeterisP 8y ago
Following the context set by article, it's worth noting that it would be far more accurate to not use the word "owned" in your sentence - you could say such UTXOs are controlled by multiple people without explicitly sharing the key, two parties can acquire control independently, but, as the article describes, that's not exactly the same as the legal concept of ownership.
- pjbyrne 8y ago
  Bingo. This is the sort of scenario for which the courts don't currently have rules to decide to whom the coins (qua krypto-property) should belong.
  - jacobush 8y ago
    I think they do. Ownership can for instance be agreed upon by regular contracts, completely orthogonal to who controls some keys. (Your accountant might, for instance.)
  - esotericn 8y ago
    The entire point of such a transaction is that the courts _do not_ decide it. The construction was specifically designed such that the person who figures out the hash collision is the owner. The courts having rules to decide whom the coins belong is meaningless in that context. Who owns a Barbie doll? Is it Mummy, Daddy or the child? It's not a matter for courts to decide because the question is meaningless.
    - pjbyrne 8y ago
      > The construction was specifically designed such that the person who figures out the hash collision is the owner... It's not a matter for courts to decide Anything is a matter for the courts to decide. Look up Popov v. Hayashi, where the courts tried to sort out who owned the ball that was Barry Bonds' 73rd home run. 2 guys caught it at more or less the same time. There was a dispute. The courts applied equitable principles to determine how ownership should be divided. The day will come when someone needs to make a similar call in relation to BTC.
      - esotericn 8y ago
        In the specific situation of petertodd's transaction, the blockchain will resolve the first solution as the owner. There is actually a technical flaw in those transactions in that a miner that is aware would just rewrite the receive address to their own as there's no signature. But ultimately a confirmation will hit the chain and transfer ownership of the UTXO. It's already a solved problem. This is literally the entire point of Bitcoin - decentralized consensus without need for trusted third parties. Courts cannot move Bitcoin from address A to B. They simply do not have the power. They can muscle in and lock people in boxes and stuff but the actual coins cannot be seized because of the nature of the system.
        PeterisP 8y ago
        Sure, courts cannot freely move Bitcoin from address A to B, but that's not really relevant. The relevant part of ownership in this context is whether moving Bitcoin from address A to B was legal, i.e. did you have the ("ownership") right to act with that Bitcoin? And the answer sometimes may be "no", even if you had the key (which you obviously did, if you made the transaction); the question "whether that transaction was fraudulent, did you commit a crime by making it" depends on who legally owned these Bitcoin, not on who knew the keys. And in many cases courts can move Bitcoin, and have done so - hardware can be seized, people forced to reveal passwords, and Bitcoin transactions executed. For example, see the multiple auctions of seized Bitcoin by U.S. Marshals Service. They can't be guaranteed to succeed, but that's nothing new (it's not like stolen goods or cash always get recovered), and they certainly can try. If someone steals something edible and eats it, courts also can't return that thing back to the owner, it doesn't mean that edible things are owned by whoever eats them. In both such cases, the courts can order (and, as much as possible, force) the culprit to compensate the rightful owner - but it matters who the rightful owner (in the opinion of the court) is, so it is meaningful to debate who owned it.

PeterisP 8y ago

Following the context set by article, it's worth noting that it would be far more accurate to not use the word "owned" in your sentence - you could say such UTXOs are controlled by multiple people without explicitly sharing the key, two parties can acquire control independently, but, as the article describes, that's not exactly the same as the legal concept of ownership.

pjbyrne 8y ago
Bingo. This is the sort of scenario for which the courts don't currently have rules to decide to whom the coins (qua krypto-property) should belong.
- jacobush 8y ago
  I think they do. Ownership can for instance be agreed upon by regular contracts, completely orthogonal to who controls some keys. (Your accountant might, for instance.)
- esotericn 8y ago
  The entire point of such a transaction is that the courts _do not_ decide it. The construction was specifically designed such that the person who figures out the hash collision is the owner. The courts having rules to decide whom the coins belong is meaningless in that context. Who owns a Barbie doll? Is it Mummy, Daddy or the child? It's not a matter for courts to decide because the question is meaningless.
  - pjbyrne 8y ago
    > The construction was specifically designed such that the person who figures out the hash collision is the owner... It's not a matter for courts to decide Anything is a matter for the courts to decide. Look up Popov v. Hayashi, where the courts tried to sort out who owned the ball that was Barry Bonds' 73rd home run. 2 guys caught it at more or less the same time. There was a dispute. The courts applied equitable principles to determine how ownership should be divided. The day will come when someone needs to make a similar call in relation to BTC.
    - esotericn 8y ago
      In the specific situation of petertodd's transaction, the blockchain will resolve the first solution as the owner. There is actually a technical flaw in those transactions in that a miner that is aware would just rewrite the receive address to their own as there's no signature. But ultimately a confirmation will hit the chain and transfer ownership of the UTXO. It's already a solved problem. This is literally the entire point of Bitcoin - decentralized consensus without need for trusted third parties. Courts cannot move Bitcoin from address A to B. They simply do not have the power. They can muscle in and lock people in boxes and stuff but the actual coins cannot be seized because of the nature of the system.
      - PeterisP 8y ago
        Sure, courts cannot freely move Bitcoin from address A to B, but that's not really relevant. The relevant part of ownership in this context is whether moving Bitcoin from address A to B was legal, i.e. did you have the ("ownership") right to act with that Bitcoin? And the answer sometimes may be "no", even if you had the key (which you obviously did, if you made the transaction); the question "whether that transaction was fraudulent, did you commit a crime by making it" depends on who legally owned these Bitcoin, not on who knew the keys. And in many cases courts can move Bitcoin, and have done so - hardware can be seized, people forced to reveal passwords, and Bitcoin transactions executed. For example, see the multiple auctions of seized Bitcoin by U.S. Marshals Service. They can't be guaranteed to succeed, but that's nothing new (it's not like stolen goods or cash always get recovered), and they certainly can try. If someone steals something edible and eats it, courts also can't return that thing back to the owner, it doesn't mean that edible things are owned by whoever eats them. In both such cases, the courts can order (and, as much as possible, force) the culprit to compensate the rightful owner - but it matters who the rightful owner (in the opinion of the court) is, so it is meaningful to debate who owned it.