[espringe]

No fraud or scam. Bitcoin users have acted very aggressively to the idea -- and felt best to censor it.

What they seem to not realize, is that double spend attacks were very viable previously (putting conflicting transactions in different part of the network), submitting double-spends directly to pools, finley attack etc.

The thing bitundo brings to the table is legitimacy. People can undo a transaction without foreknowledge they will need to. This is nothing but a good thing for the bitcoin network, and it reminds people that 0-confirmation transaction never were, and never will be safe.

Edit: it's back!

[mike_hearn]

You're the guy who created it, aren't you?

Double spends are not currently "very viable", as indicated by the fact that they were not happening and accepting instant payment is the standard. This is objective reality, not something you can argue away. A different world being theoretically possible does not translate into it magically happening with no effort. You are making an effort to change our happy situation for your own profit, in other words, to make Bitcoin less useful over the long run to benefit yourself in the short run. I can't tell if you're motivated by greed or a particularly poorly thought out world view.

Also, why are you claiming this is somehow specific to unconfirmed transactions? Corrupt miners can also rewrite the block chain. If you get paid enough and have enough hash power, why not see if you can overtake the chain head? So don't claim it's somehow specific to unconfirmed transactions. It isn't.

Bitcoin fundamentally assumes that the majority of mining power is "honest", defined to mean following the rules laid down by Satoshi in the core software. You can see this by simply reading the white paper:

"The system is secure as long as honest nodes collectively control more CPU power than any cooperating group of attacker nodes."

(last sentence, first page)

You are attempting to bribe miners to become "dishonest" and "attack the network" in Satoshi's language. If enough people did what you suggest, the system's fundamental assumption would be invalidated and the entire network would break. If merely a small number of people do it, it just makes the system unreliable, untrustworthy and pushes people towards centralised fixes like payment processors that levy higher fees, trusted third parties that prevent double spending, secure hardware, etc. All things that increase Bitcoin's costs and reduce its competitiveness vs regular banking. Doing this doesn't help anyone or prove any point, it just adds sand into an otherwise useful system by increasing transaction costs.

tl;dr you are like a kid kicking down someone's sandcastle on a beach, then saying "they should have been guarding it better, anyone could have done what i did!".

[nhaehnle]

To be fair, if comparing Bitcoin to a sandcastle is a fair comparison, then it's better for this to be made obvious to everybody before it reaches critical mass.

Perhaps more importantly, this feature doesn't actually rely on miners being dishonest. There is no rewriting of the blockchain going on. All that is required is that miners are greedy. That is, when two conflicting transactions are in the mempool, it requires that miners prefer the transaction that comes with a higher fee.

[mike_hearn]

I think people involved with it over the long term have always said that it's a risky experiment that might fail. Bitcoin resembles a sandcastle far more than a honey badger, that's for sure.

"Honesty" is defined to mean "following the rules". The first seen rule is a part of that set. BitUndo isn't attempting to fork the chain today, but they certainly could - it's a simple extension of their model. Double spending for a fee doesn't really care whether a tx is unconfirmed or not, it simply alters the price charged.

[JetSpiegel]

That doesn't change the fact the castle isn't secure. This is a wakeup call for anyone relying on 0-confirmations transactions.

[mike_hearn]

Security isn't a binary yes/no thing and double-spending-for-a-fee does not require unconfirmed transactions. Confirmed txns can be replaced too, it just costs more.

[mpyne]

> Bitcoin users have acted very aggressively to the idea -- and felt best to censor it.

It's not even ironic anymore when they respond in this fashion. They'd probably even remind you that only the government can technically "censor" something, and that if people want accurate news on Bitcoin they are free to pick a competitor to /r/bitcoin that will provide it.