What kind of adoption is held back with 10min block time versus 2.5 minute block time?
- everyday in-shop purchases shops can accept non-confirmed transactions -- the risk when handled properly is minimal compared to things like counterfeit cash or credit back claims
Let's say you are buying $250 at grocery store. Really they are going to accept 0 or 1 confirmation? Chances are they will want 6 or more. It is a definite issue in my mind.
Best solution I've seen is to use trusted 3rd parties using 2 of 2 multisig transactions (
greenaddress.it is rolling this out now I think). This then allows merchant to accept 0 confirmation transactions and trusts that the 3rd party won't double spend. Both merchant and customer have to be using the same 3rd party though, so that is a drawback but merchants could accept payments from multiple 3rd parties.
Steps:
- Customer can send funds in advance to a multisig address requiring their signature and 3rd party sig.
- At payment time, customer and 3rd party both sign a transaction spending the multisig transaction and sending payment to the merchant.
- Merchant is trusting 3rd party not to double spend.
- Merchant gets sent copy of transaction presumably using payment protocol, so they don't even wait for it to get propagated through the bitcoin network.