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Comment by jimktrains2 | Hacker News Reader

But if you handle tx properly it doesn't disrupt your system.

The seriousness of this attack is that several major bitcoin services lost a lot of money because of it. It's an attack.

It's an attack, it's just not an attack on Bitcoin.

This is mincing words. It's an attack on bitcoin. Many major exchanges were shuttered while they dealt with it, for example.

It's certainly not an attack on not-bitcoin, so therefore it's an attack on bitcoin.

There's an attack on credit cards because Target had a breach!

See, I can say ridiculous things too. Someone using bitcoins didn't follow protocol and as such as scammed out of money. This isn't a bitcoins-protocol issue, this is a people issue.

Note that the other exchanges are up now, very quickly after everyone stopped to check themselves.

The Target hack certainly disrupted the credit card system, by causing a lot of reissued cards.

That doesn't really disrupt the system though. It's not causing issues for anyone who hasn't had their card canceled and reïssued.

Bitcoin the protocol? Bitcoin the idea? Bitcoin the network? Bitcoin the whole ecosystem?

I would argue it was an attack on Bitcoin the ecosystem, due to an _oddity_ of Bitcoin the protocol. Bitcoin the idea is still fully alive. The attack worked from within Bitcoin, the network.

This causes another problem. Even if you have a lot of coins from a former transaction, when you spent a little the remainder coins (change) have to be blocked for 1 hour (6 blocks) until the transaction is "confirmed".

The standard client just assumes that the transaction is legit and you can use the remaining coins immediately. But to use these coins the program has to know the ID of the transaction.

But due to the malleability, it's possible that the ID that is generated in your client is not the same ID that is finally added to the blockchain. If you use the original ID and it is changued, then the next transactions will be invalid. So you must wait to see the final ID and use it to create the next transactions.

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