Hi,
I believe most of the people in the world are honest enough to not even try to double spend ( I may be naive, but i prefer to live like this than to consider everyone is a thief)
I don't think so, but we can at least say that it's less risky in-person..
Moreover it's more cumbersome to make a double spend that it's usually implied, and if people are going to Burger King because they don't want to bother cooking... There is a low probability they actually try to make a double spend for a 5 dollars worth transaction if it's not "for the fun" (not considering RBF though).
Anyway, I was thinking how easy is it to do a double le spending in this case? Have anyone ever tried?
I've tried and succeeded on a low-hashrate shitcoin I created for a series of workshop I organised.
The transaction broadcast is almost instantaneous across all the network. Does broadcast time makes any difference? I believe most wallets won't let you double spend (never tried..)
You need to target miners if you are trying to double spend a
final transaction.
In the example I was talking about above I cheated because I was the owner of the only source of the hashrate so ... ^^
My question is:
If you have a transaction which is already broadcasted across all full nodes mempool, if you send a other one with a higher fee, will nodes recognize it as a legit transaction?
Not if the transaction is final, but they will accept a block containing the new one.
If it is possible, isn't it a good idea to create a BIP proposing to disallow to double spend of a transaction already in mempool? What would be the cons against that?
The block chain is shared across the nodes, everyone has the same. The mempool is not at all, so consensus decisions cannot be made out of it.
That said, that's already the behavior of bitcoin-core (for, once again, non final transactions). But another implementation allowing this wouldn't fail out of consensus.
Newbie question but I always thought zero confirmation transactions are interesting.
At least as much as is mempool policy
PS: If you're looking for a double spend on Bitcoin, iirc Peter Todd double spent some Reddit Gold some time ago. You could find some interesting stories.