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What the CoinWallet.eu tx-flood stress-test means for you and how to deal with it (gist.github.com)

petertoddPeter Todd - Bitcoin Expert が 投稿

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トップ新着論争中古い順Q&A

[–]coins101 19ポイント20ポイント  (1子コメント)

Pretty decent and very informative overview of fees paid to miners.

Thanks

[–]petertoddPeter Todd - Bitcoin Expert[S] 9ポイント10ポイント  (0子コメント)

Glad you liked it!

[–]Plesk8 5ポイント6ポイント  (2子コメント)

Correction: Coinbase used to have 0.0002 for their default fee. However, for the past several months, including my tx today, I've seen Coinbase's fee consistently at 0.0001.

edit: I've emailed their support letting them know about the difference.

edit2: They responded saying they'd have somebody update the page. Here is the page in question:

https://support.coinbase.com/customer/portal/articles/815435-does-coinbase-pay-bitcoin-miner-fees-

[–]petertoddPeter Todd - Bitcoin Expert[S] 4ポイント5ポイント  (1子コメント)

Thanks! As it's a direct quote though, I'll leave it as-is.

[–]Plesk8 3ポイント4ポイント  (0子コメント)

indeed they do say exactly that.

I've sent a message into their support telling them about the discrepancy I'm seeing.

edit: They responded saying they'd have somebody update the page. Here is the page in question:

https://support.coinbase.com/customer/portal/articles/815435-does-coinbase-pay-bitcoin-miner-fees-

[–]corbendallas22 1ポイント2ポイント  (0子コメント)

But we can still script our transactions and pay whatever fee we want, right?

[–]usrn 7ポイント8ポイント  (0子コメント)

Daily Peter Todd dose.

[–]i8e 3ポイント4ポイント  (2子コメント)

What does this testing prove? The last stress test seemed like idiots trying to prove that miners will not process their penny-fee transactions first and instead actually does what the software says it does.

[–]smartfbrankings 1ポイント2ポイント  (0子コメント)

It's trying to prove that the sky will fall if we don't kowtow to Hearn's demands.

[–]ProHashing 0ポイント1ポイント  (0子コメント)

It won't prove anything. In order to make a difference in the cost of using the network, they would need to pay fees at that cost.

But right now, they're only paying the going rate, so that won't increase fees much. If they want to increase the cost of transactions by 10x, then they would need to pay 10x the money, which quickly becomes unaffordable.

The most likely outcome to this attack is that they will simply waste all their money and things will return to normal. It's not a big deal for you or me to pay 2 cents instead of 1 cent. As they put out more transactions, they're going to have to pay more, and as is already occurring, their funds are being depleted more quickly than anticipated.

I don't understand the purpose of this attack, since the fees they are spending aren't high enough to significantly increase costs. All they're doing is making miners like us rich, and burning large numbers of bitcoins in wallets too small to be spent without enormous fees in the future.

[–]viners 1ポイント2ポイント  (10子コメント)

It's 4 minutes past and I haven't seen any spam on the blockchain. Are they running late?

[–]petertoddPeter Todd - Bitcoin Expert[S] 1ポイント2ポイント  (8子コメント)

I saw a bunch about an hour ago, as though they did a quick test run; be pretty funny if they chicken out!

[–]shrem_way 1ポイント2ポイント  (7子コメント)

Every block has been filled completely in the last 2 hours. What metrics are you using?

[–]petertoddPeter Todd - Bitcoin Expert[S] 11ポイント12ポイント  (6子コメント)

Like I said, there was a quick burst of txs in a few minutes above the normal background rate.

From what I can see right now they're doing the smart thing, a slow but consistent attack that gradually builds the size of the mempool. Getting tx flood attacks to actually propagate across the network is tricky; looks like they're doing this one correctly.

[–]BashCo 7ポイント8ポイント  (4子コメント)

You can see the tx burst here:

http://statoshi.info/dashboard/db/transactions?panelId=6&fullscreen

[–]statoshi 5ポイント6ポイント  (0子コメント)

Please bear with me if the charts don't load; I've been trying to figure out this issue for a while...

[–]Willidungl 2ポイント3ポイント  (0子コメント)

Very cool site

[–]moral_agent 1ポイント2ポイント  (0子コメント)

Haha, you're eating this up. Pretty exciting to get something empirical for a change...

What do you think the "real" solution to DDOS attacks would look like? By DDOS attack I mean any temporary extreme increase in tx volume.

[–]UpGoNinja 1ポイント2ポイント  (1子コメント)

Minor typo:

... you're transactions should go through

The "fee marketplace" argument for 1MB blocks is out of touch with today's reality, but improvements in wallet software would make a marketplace work pretty painlessly. Still I would want the block rate to be dropped down to Litecoin levels. This way you could wait 1-5 minutes for the first block and add child-pay-parent or whatever to bump the priority if it wasn't included as you expected. Waiting 5-30 minutes for a block is unnecessarily slow.

/u/petertodd, what do you think about targeting shorter block times?

[–]petertoddPeter Todd - Bitcoin Expert[S] 3ポイント4ポイント  (0子コメント)

Thanks.

Shorter blocktimes significantly increase the effectiveness of a whole variety of attacks; it's not a linear relationship where you can just halve the block interval to double the overall transaction capacity. Rather for a given security level you'll get something less than double the capacity, and figuring out exactly what is that tradeoff is something people are still studying.

[–]jstolfi 0ポイント1ポイント  (21子コメント)

Transaction fees are a supply and demand marketplace.

Glad that he did not write "a free market", because it is anything but. In a free market the consumers know beforehand what each supplier charges and delivers, and can freely choose the supplier. Neither will be true in bitcoin's "fee market".

When you send a transaction your wallet would have a threshold value for what level of fee you don't care about - "if the fee costs less than 10 cents, don't ask me for confirmation, just send it". In cases where getting into the next block would cost more than your threshold setting, your wallet would let you know and give you an estimate for how long you might have to wait at various fee levels.

Except that (1) the wallet will have no way to compute those estimates, since they also depend on what other desperate clients will do to push their payments to the front of the queue; and (2) once the traffic gets close to capacity, the queues will become increasingly unstable, so the delay would become unpredictable even ignoring the other clietns; and (3) once a backlog develops, the expected delay becomes ~1 block if the fee is above some threshold, or infinite below it; where the threshold is continuously varying as other clients try to adjust their fees to get above it. While the RBF policies allow clients to jump the queue, they make them more unpredictable.

Mike Hearn explained in detail why the "fee market" will not work, in his crash landing blogpost. Unlike the vague assurances of the small-blockians, his analysis is based on well-known results of queue theory (which are easy to understand once they are pointed out. As far as I know, there has been no rebuttal to that analysis.

[–]i_wolf 2ポイント3ポイント  (2子コメント)

Glad that he did not write "a free market", because it is anything but. In a free market the consumers know beforehand what each supplier charges and delivers, and can freely choose the supplier. Neither will be true in bitcoin's "fee market".

I don't care which supplier will send my transaction, don't tell me what I "require", all I want to know if it comes through and if the price is acceptable to me. I know what they deliver after making the first transaction, or by asking other customers.

Except that (1) the wallet will have no way to compute those estimates

Exactly, this is why trying to "calculate" or "guess" fees is just silly. Miners should announce their fees explicitly. To do that, they should care about fees in the first place, which is not true until the block reward is sufficient for them.

Mike Hearn explained in detail why the "fee market" will not work, in his crash landing blogpost

His scenario holds true for attempt of artificially enforcing a "market" with a hard limit, when miners don't care about fees yet. When block reward diminishes, they will be fully capable of settings their own fees and limits to control the amount of transactions.

[–]jstolfi -1ポイント0ポイント  (1子コメント)

Miners should announce their fees explicitly.

As I have already explained, even if all miners post "my minimum fee is 0.005 BTC", a transaction that pays 0.010 BTC may stay forever on the queue, as soon as a persistent backlog develops. On the other hand, every miner will be better off processing a transaction that pays 0.001 BTC, if there are not enough higher-fee transactions to fill his block. So, a "minimum fee" posted by the miners is useless information.

[–]i_wolf 0ポイント1ポイント  (0子コメント)

If backlog develops, then the price is too low.

Even if McDonalds posts "minimum hamburger price is 0.005 USD", a buyer that pays 0.010 USD may stay forever, as long as persistent queue develops. Solution - raise the price high enough to eliminate the queue (to $1). The higher the price => the fewer customers there are.

If there's high demand, it's better to sell fewer items for a higher price.

So, a price is only useless if it's too low.

[–]GibbsSamplePlatter 5ポイント6ポイント  (4子コメント)

"Former Google developer yells at clouds"

edit:Ok, to flesh out the joke, there is literally no way to run a p2p network without an anti-DoS mechanism. The best one we have is fees. Right now they only reason we don't have consistently full blocks is hard-coded dust rules and bad propagation of blocks. Mike's blog posts are all "real solutions are too hard", and his "fix" is to just make another PayPal.

[–]jstolfi -2ポイント-1ポイント  (3子コメント)

and his "fix" is to just make another PayPal.

AFAIK he has no fix. He just points out that the fee market, that small-blockians are counting on, will not work; so he proposes to increase the block size in order to push the disaster further in the future, until some genius finds a way to make fees work.

And if anyone is proposing a PayPal-like solution, it is Blockstream with the Lightning Network...

[–]goalkeeperr -1ポイント0ポイント  (2子コメント)

which they didn't invent? they just started looking into it, isn't it true?

[–]petertoddPeter Todd - Bitcoin Expert[S] 2ポイント3ポイント  (1子コメント)

Yup. They're just paying to make it happen, as open source software, in part because Mike Hearn criticized them for not proposing concrete alternatives to raising the blocksize...

[–]goalkeeperr 0ポイント1ポイント  (0子コメント)

lulzy by the day this coupé

[–]petertoddPeter Todd - Bitcoin Expert[S] 3ポイント4ポイント  (12子コメント)

Mike Hearn's analysis is completely irrelevant to the situation: like it or not what I described is how Bitcoin actually works and the best we're going to do is make a small change in the cost of such attacks. As I mentioned in my post, a 8MB blocksize increase only increases the cost of this attack to $40k - still chump change.

No-one is proposing that there be no blocksize limit, and as long as we have a limit, you'll have to bid for transaction space. If anything, I expect the problem to get even more acute as more and more different classes of users start using Bitcoin for a wider variety of things, e.g. securing financial records, timestamping, etc.

[–]jstolfi 9ポイント10ポイント  (11子コメント)

Mike Hearn's analysis shows that, if there is a backlog of fee-paying transactions, there will not arise a nice "fee market" that small-blockians assume, but chaos; because of the way that bitcoin actually actually works.

And the small-blockians further assume that all the wallet programs out there should be modified to remain connected to the network and continuously monitor the queues (not just the mined blocks), possibly interacting with the user several times to ask for permission to increase the fees. That is a big change in the bitcoin transaction model, from the user's viewpoint. Calling it a "trivial change" is the Guiness of irresponsability...

[–]petertoddPeter Todd - Bitcoin Expert[S] 9ポイント10ポイント  (10子コメント)

I think you're missing my point here: regardless of whether he is right or wrong, no-one is proposing a solution to that problem that would actually solve the problem he believes he identified. The blocksize is limited and will inevitably be used to capacity; there's just not much we can do about it.

If he's right, then Bitcoin doesn't work and that's that.

[–]jstolfi 1ポイント2ポイント  (9子コメント)

The small-blockians are saying "let the network saturate, there will be a fee market that will keep it usable for good clients and drive only bad clients away; and the sooner that happens, the better". He is saying "the fee market will not work, so the only thing we can do is increase the blocksize for now, and hope someone will invent a fee mechanism that works before saturation is inevitable."

[–]petertoddPeter Todd - Bitcoin Expert[S] 9ポイント10ポイント  (8子コメント)

So... buy maybe a year or two at best of growth, based on a problem we haven't actually seen yet, at the high cost of more centralization, with no plan other than "hope one or two more years solves it"?

That's not very convincing. And frankly I have a lot more faith in wallet authors' ability to solve problems with a fire under their feet than Mike does.

[–]AManBeatenByJacks 2ポイント3ポイント  (1子コメント)

I thought the idea was solving the problem but not making use of bitcoin prohibitively expensive. If theres hardly any space on bitcoin people will use an alt rather than pay a miner a $5 transaction fee.

[–]t9b 0ポイント1ポイント  (0子コメント)

This. A hundred times. Sorry Bitcoin - all this squabbling is not doing us users any favours.

I jumped ship when I realised there is no way out if this impasse without a catastrophic failure, and I'm sorry I'm not seeing any cmpromise.

[–]handsomechandler 1ポイント2ポイント  (0子コメント)

If the problem of higher transactions never arrives how is there more centralization?

[–][削除されました]  (4子コメント)

[deleted]

    [–]petertoddPeter Todd - Bitcoin Expert[S] 5ポイント6ポイント  (3子コメント)

    Buttcoiner's hat? Geeze man, that's my job!

    [–]jstolfi 1ポイント2ポイント  (2子コメント)

    You are a newbie over there. Please respect your elders.

    [–]petertoddPeter Todd - Bitcoin Expert[S] 8ポイント9ポイント  (0子コメント)

    I only engage in voluntary, non-hierarchical, decentralized trolling.

    [–]goalkeeperr -3ポイント-2ポイント  (0子コメント)

    masterbutter

    [–]kaibakker 0ポイント1ポイント  (1子コメント)

    Make websites with easy to understand displays of what the current mempool backlog is, and what fee/KB is needed to get to the front of the queue. We've done a great job for Bitcoin price charts, lets extend that to transaction fees."

    It would be cool to build something like this on top of Toshi, it should be pretty easy actually. Does anyone have an idea how to host Toshi for a reasonable price?

    [–]coinlock 0ポイント1ポイント  (0子コメント)

    That 300+ gb database doesn't help much. Define reasonable? :)

    [–]BitsenBytes -2ポイント-1ポイント  (8子コメント)

    We should not be doing performance testing in a production environment. Anybody who does performance testing knows that things can go very wrong during such tests and that's why we do them in proper testing environments.

    Little children playing with fire...

    [–]bitcoinsharp 10ポイント11ポイント  (3子コメント)

    And we have a test net. People like me are trying to live our lives on this network. I wish they would not treat it like an object on which to having pissing contest.

    [–]cypherdoc2 -1ポイント0ポイント  (1子コメント)

    please submit a request to your local friendly core dev.

    [–]bitcoinsharp -1ポイント0ポイント  (0子コメント)

    My request is for "CoinWallet.eu" and the like to stop doing stress tests. I am afraid its a thing now, some c**ts will probably do on bitcoin black friday to make a point.

    [–]jstolfi -1ポイント0ポイント  (0子コメント)

    It was meant to be an experiment. Unfortunately people have hijacked it and are trying to use and sell as a product...

    [–]GibbsSamplePlatter 11ポイント12ポイント  (2子コメント)

    I mean if it goes really wrong, I'd rather know now. That would mean Bitcoin is literally broken and easily so.

    Full blocks are the natural state of Bitcoin. The only reason it's not full is because of dust rules and propagation still sucks.

    [–]justusranvier 4ポイント5ポイント  (1子コメント)

    Full blocks are the natural state of Bitcoin.

    There exists an equilibrium point at which the willingness of miners to produce blocks of a certain size at a particular price exactly matches the willingness of Bitcoin users to create that volume of transactions at that same price.

    If there is a block size limit which is set below that equilibrium point, then the "natural state" of blocks is to be full, if by "natural state" you mean "artificially restricted state."

    https://www.youtube.com/watch?v=gVq5oh3-JXc

    [–]bitcoinsharp 1ポイント2ポイント  (0子コメント)

    731 kb blocks being considered "full" is most definitely not the natural state of bitcoin.

    [–]mmeijeri -1ポイント0ポイント  (0子コメント)

    That's exactly what we should be doing.

    [–]Willidungl 0ポイント1ポイント  (3子コメント)

    Already fees above 25 BTC to be collected

    [–]petertoddPeter Todd - Bitcoin Expert[S] 6ポイント7ポイント  (2子コメント)

    You're getting that from blockchain.info right? Chances that's from invalid transactions that their custom node implementation is incorrectly accepting; on my Bitcoin Core nodes I'm seeing 0.5BTC in fees at this moment.

    [–]Willidungl 0ポイント1ポイント  (1子コメント)

    Correct. I see, thanks!

    [–]petertoddPeter Todd - Bitcoin Expert[S] 5ポイント6ポイント  (0子コメント)

    FWIW, here's my mempool watching script: http://0bin.net/paste/qKlWS5AXVaO7tvCO#-0cuJSvIQJXFb15/xJpE89jHU/4XdSGetudHEmbVfMP

    Needs python-bitcoinlib v0.4.0 to run.

    [–]jabetizo -1ポイント0ポイント  (0子コメント)

    CoinWallet.eu is only spending $5k flooding the network; even an 8MB blocksize increase can only raise the cost of that attack to $40k, which is still very affordable. For instance an attacker looking to manipulate the Bitcoin price could probably afford to spend $40k doing it with the right trading strategy; let alone governments, banks, big businesses, criminal enterprises, etc. to whom $40k is chump-change.

    With a 100MB block size, a prolonged attack like this would significantly increase the bitcoin price. Anyone wanting to harm Bitcoin would not like to do that.

    [–]GibbsSamplePlatter -1ポイント0ポイント  (2子コメント)

    I guess I was super-confused for a long time. I thought coin age mattered somewhat... I guess that's only for network propagation.

    Makes sense.

    [–]petertoddPeter Todd - Bitcoin Expert[S] 3ポイント4ポイント  (1子コメント)

    It does, but miners are increasingly turning off the free area, and other than Bticoin Core no wallets that I know of output zero-fee transactions.

    [–]Fizzgig69 -2ポイント-1ポイント  (0子コメント)

    THANK YOU PETER TODD! I was thinking last night...why doesn't anyone actually frame the problem in a way that makes sense? This entire community seems to be infested with bad ideas which have been built on false assumptions. We need clarity and leadership of ideas.

    The capacity issue is finally coming! Let's take this step by step and organize our thoughts into a plan that will transition Bitcoin into the best future version it can be.

    Right now the winning miner gets to scoop up some fees for some extra bitcoin, this is not at all how fees should work, it provides no incentives and serves no purpose, it is the result of an anti-spam patch. We never dealt with the issue back then so let's frame the problem in the right way and finally slay this beast.

    The "fee" market works opposite of the "bitcoin" market in the sense that miners are the bidders, and users put up the offers as fees. As long as there are a finite number of transactions, fees can maintain a level of close to 0. By raising the block limit we are trying to live in an era where the number of transactions coming in are finite and small enough to deal with (i.e. working well under capacity). We will solve the problem better if we are working in an environment in which we feel the effects of the problem. If we don't feel the problem, we don't solve it...

    So let's plan on more transactions, which means bigger queues. We need better ways of incentivizing miners to include the best fees, we need an intuitive process by which a transaction can be submitted and reliably mined x blocks into the future, one that the user can understand, see in real time, undo if not yet confirmed, and resubmit new fee values give better block estimates.

    Only Bitcoin can deal with these problems due to our popularity in the cryptocurrency space. I understand if you are afraid Bitcoin will choke and die due to overcapacity but Bitcoin is resilient, we should focus on the fundamentals.