[fragsworth]

My understanding is it works like this in Ethereum:

The miners can run any arbitrary code ("a contract") that you write, and this code is verifiable and trusted by everyone once it's been uploaded to the blockchain. The contracts can read/write arbitrary things in the blockchain and send coins to anyone you want, determined by the code you write.

There's a "gas price" that you have to pay for each operation you tell the miners to execute. However, the operation "EXTCODESIZE" evidently has too low of a cost, allowing someone to pay to have it executed enough times to noticeably slow the miners down for shits and giggles.

Someone correct me if I'm wrong?

[TD-Linux]

Sounds right. In Bitcoin, there are also some opcodes that are more expensive than others (hashing) which have been limited to a certain count per block.

[zorked]

Is there another angle? E.g. can the attacker have precomputed the results of those operations and now he can mine faster than anybody else or something like that?

[valarauca1]

Yes you can game the network by writing your own Ethereum Mining Client. Introducing a ton of code. Selectively ignoring code. BUT this isn't smart. You are devaluing the currency you are deriving profit hurting your profit margin.

Furthermore you need to maintain plausible deniability. THIS IS HARD. If Ethereum catches you, they'll just hard fork. So your average blocked claims can't change by a large amount. So in reality you already need to 1st/2nd sigma miner, then increase your profits by maybe 20-30%. This is a lot of risk, and a ton of work.

Most likely it is just somebody doing it for the lulz

[deegles]

I'm disappointed that the devs established the precedent that if things go south they'll hard-fork. It reduces the incentive to avoid risky behavior. Having a centralized roll-back/bailout authority is what led to too-big-to-fail banks.

[TD-Linux]

Yes, it's possible to do that. I'm not sure if the current miner is, though.

[paavokoya]

Just means the market needs to raise the prices. In bitcoin this is similar to raising transaction fees to add a disincentive for DDOS attacks.

Right now, it seems ethereum is just an almost-free VPS service and people are surprised that actors are taking advantage of it.

[komaromy]

> almost-free VPS service

I guess, if most VPS services cost >$5/minute: https://www.reddit.com/r/ethtrader/comments/53xt58/daily_dis...

[makomk]

This isn't quite sufficient, because the prices are set by miners but the transactions have to be processed by every single full node in existence. That's why Bitcoin has a hard upper limit on the complexity of processing any given block.

[nathan-wall]

> That's why Bitcoin has a hard upper limit on the complexity of processing any given block.

Similarly, Ethereum has a gas limit per transaction.