One way to expedite small transactions would be to have all of the miner shun all further transactions by someone who has attempted a double spend, then if someone only wants to transfer less than 50% of their wealth then it can be assumed that it is a valid transaction because their expected return with a successful double spend is exactly what they would do with a valid transaction.

As far as I understand all that would be needed for this to be put into place would be to update the protocol, the blockchain can be preserved. Am I wrong? Is this a bad idea?

1 Answer 1


This won't work. Consider:

  1. I send you 1 Bitcoin from an account that has 2 Bitcoins to an account of yours that has 99 Bitcoins.

  2. Your account now has 100 Bitcoins. You rely on this new system and consider my transaction to you confirmed. You send the 1 Bitcoin I sent you and 9 other Bitcoins you had before to someone else.

  3. I double spend the 1 Bitcoin I sent you. Your transaction of 10 Bitcoins is now a double spend as well.

Now, there are two choices and they both suck:

  1. Only my account is frozen. But anyone who relied on your transaction is screwed with no recourse. And only my 1 Bitcoin is frozen even though someone got screwed on a 10 Bitcoin transaction from an account holding 100 Bitcoins.

  2. Your account is frozen. But you did nothing wrong but rely on my transaction, and now your 100 Bitcoins are frozen.

You and I may or may not be in collusion, and there's no way to tell which just from looking at the transactions.

You are operating on a set of false assumptions about how double spends actually occur.

  • Hmm, I am not sure what the best format for responding is, but here goes: Once that person has double spent the 1 bitcoin, then the network would realize that the person attempted a double spend. Because the double spend has value of half or less than their total number of bitcoins then the network can simply say that they spent both of their bitcoins, they simply go to the people they tried to scam. The 10 bitcoins you just mentioned is a red herring. Sorry if I didn't explain it properly. Feb 21, 2013 at 21:44
  • @PeterMichealLacey-Bordeaux: So you're suggesting option one above? But then the person those 10 Bitcoins were sent to is screwed. He relied on those 10 Bitcoins being sent to him, he'll never get them, and only 1 Bitcoin is frozen. So your scheme doesn't make transactions reliable, it just lets people get screwed even through on fault of the sender or the recipient! Feb 21, 2013 at 21:47
  • Sorry I guess freezing the accounts wouldn't work, you would have to just take the bitcoins out of the offending account. I don't really see how the 10 bitcoin transaction is tainted, but I just figured out why this system wouldn't work. You have 2 bitcoins and simply make 3 transactions giving out 1 bitcoin. Sorry for the confusion. Feb 21, 2013 at 21:49

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