Title: Is it possible to have two transaction IDs that are exactly the same? Post by: TeraPool on July 13, 2011, 01:20:18 AM Or would that be considered a collision of some sort? What exactly is a transaction id? A hash of some sort I presume?
I couldn't find much about transaction ids in particular on the wiki. How would the bitcoin client treat two separate transactions with identical transaction ids? Title: Re: Is it possible to have two transaction IDs that are exactly the same? Post by: josell on July 13, 2011, 01:50:21 AM Yes, it is possible... But is very very very unprobable. They are more possible directions that atoms on the hole earth, but im not really sure.
Title: Re: Is it possible to have two transaction IDs that are exactly the same? Post by: TeraPool on July 13, 2011, 03:44:26 AM Thanks for that.
That's what I thought. Since blockexplorer allows you to search by transaction id... you should not be able to have a duplicate one I would think. Title: Re: Is it possible to have two transaction IDs that are exactly the same? Post by: theymos on July 13, 2011, 03:58:37 AM Transaction IDs are SHA-256 hashes of transactions. It's very safe to use them as unique IDs, and it's a waste of time to try to detect collisions.
It is possible (though very rare) for the exact same transaction to appear twice in the block chain, however. Title: Re: Is it possible to have two transaction IDs that are exactly the same? Post by: davux on July 13, 2011, 07:44:02 AM It is possible (though very rare) for the exact same transaction to appear twice in the block chain, however. Can you please explain under what circumstances this could happen? I couldn't find anything. Title: Re: Is it possible to have two transaction IDs that are exactly the same? Post by: Maged on July 13, 2011, 07:52:51 AM It is possible (though very rare) for the exact same transaction to appear twice in the block chain, however. Can you please explain under what circumstances this could happen? I couldn't find anything. Title: Re: Is it possible to have two transaction IDs that are exactly the same? Post by: JoelKatz on July 13, 2011, 02:47:23 PM You can maliciously, or stupidly, create two transactions with the same ID. The easiest way is to mine two blocks and include in each one only a single transaction -- the coinbase transaction, with the same payout address, same payout amount, and the same coinbase.
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