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Title: Can TXID be caculated before TX commited? Post by: wangsw on May 18, 2013, 03:17:51 AM Hello all!
Is TXID predictable before transaction broadcast to peers? Or in other words,can someone choose a certain txid he want when broadcast a transaction? Title: Re: Can TXID be caculated before TX commited? Post by: kfreds on May 18, 2013, 02:38:21 PM Hello all! Is TXID predictable before transaction broadcast to peers? Or in other words,can someone choose a certain txid he want when broadcast a transaction? Hi! Yes, it's a hash based on the content of the transaction. See the bitcoin wiki or this question: http://bitcoin.stackexchange.com/questions/2859/how-are-transaction-hashes-calculated The answer to the second question is no. Furthermore that would be an undesirable feature of a hash function. See "preimage attack". Title: Re: Can TXID be caculated before TX commited? Post by: wangsw on May 19, 2013, 02:55:34 AM Hello all! Is TXID predictable before transaction broadcast to peers? Or in other words,can someone choose a certain txid he want when broadcast a transaction? Hi! Yes, it's a hash based on the content of the transaction. See the bitcoin wiki or this question: http://bitcoin.stackexchange.com/questions/2859/how-are-transaction-hashes-calculated The answer to the second question is no. Furthermore that would be an undesirable feature of a hash function. See "preimage attack". Title: Re: Can TXID be caculated before TX commited? Post by: grue on May 19, 2013, 03:04:51 AM So we can still have a hash set to choose from by select different vin or nLockTime without ruin a transaction. yes. you can change the txids as much times as you want, but there's no easy way to get a specific txid. |