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> If the proof-of-work system is actually a crypto miner, such that visitors end up paying the site for the content they host Unsure how that would work. If th

by diggan 1y ago

> If the proof-of-work system is actually a crypto miner, such that visitors end up paying the site for the content they host Unsure how that would work. If the proof you generate could be used for blockchain operations, so that the website operator could be paid by using that proof as generated by the website visitor, why shouldn't the visitor keep that proof to themselves and use it instead? Then they'd get the full amount, and the website operator gets nothing. So then there is no point for it, and the visitor might as well just run a miner locally :)

Retr0id 1y ago
If the user mined it themselves and then paid the site owner before accessing the site, they'd have to pay a transaction fee and wait for a high-latency transaction to commit. The transaction fee could dwarf the actual payment value. Mining on behalf of the site owner negates the need for a transaction entirely.
- viraptor 1y ago
  (unnecessary)
  - Retr0id 1y ago
    I know this.
    - viraptor 1y ago
      Responded to wrong comment, sorry
odo1242 1y ago
The company Coinhive used to do this before they shut down. Basically, in order to enter a website, you have to provide the website with a certain number of Monero hashes (usually around 1,024) that the website would send to Coinhive’s miner pool before letting the user through. It kinda worked, except for the fact that hackers would try to “cryptojack” random websites by hacking them and inserting Coinhive’s miner into their pages. This caused everyone to block Coinhive’s servers. (Also you wouldn’t get very much money out of it - even the cryptojackers who managed to get tens of millions of page views out of hacked websites reported they only made ~$40 from the operation)
- kbenson 1y ago
  If attackers only made ~$40 fora good amount of work, seems like it would have resolved itself if the scheme was left to run itself to conclusion before people started blocking coinhive in (what sounds like from your description) a knee-jerk reaction. Then again, I'm sure there's quite a bit of tweaking that could be done to make clients submit far more hashes, but that would make it much more noticeable.
- hoppp 1y ago
  That $40 now coud be in the thousands if they didn't spend it Xmr was cheaper back then.
viraptor 1y ago
Have a look at how mining pools are implemented. The client only gets to change some part of the block and does the hashing from there. You can't go back from that to change the original data - you wouldn't get paid. Otherwise you could easily scam the mining pool and always keep the winning numbers to yourself while getting paid for the partials too.
- mistercow 1y ago
  Just to make sure I understand this (and maybe clarify for others too), because my understanding of proof-of-work systems is very high level: When you mine a block, you’re basically bundling up a bunch of meaningful data, and then trying to append some padding data that will e.g. result in a hash that has N leading 0 bits. One of the pieces of meaningful data in the block is “who gets the reward?” If you’re mining alone, you would put data on that block that says “me” as who gets the reward. But if you’re mining for a pool, you get a block that already says “the pool” for who gets the reward. So then I’m guessing the pool gives you a lesser work factor to hit, so some value smaller than N? You’ll be basically saying “Well, here’s a block that doesn’t have N leading zeroes, but does have M, leading zeroes”, and that proves how much you’re working for the pool, and entitles you to a proportion of the winnings. If you changed the “who gets the reward?” from “the pool” to “me”, that would change the hash. So you can’t come in after the fact, say “Look at that! N leading zeroes! Let me just swap myself in to get the reward…” because that would result in an invalid block. And if you put yourself as the reward line in advance, the pool just won’t give you credit for your “partial” answers. Is that about right?
  - mistercow 1y ago
    Just to tack onto this, the one thing you could do is just deny real rewards. If someone wants you to take part in their pool in order to load a webpage, you could just refuse to submit any block that will actually pay out. This wouldn’t benefit you, but it would punish them for trying to make you spend resources on their behalf. I wonder if there’s a way to prevent that.
lurkshark 1y ago
This system actually existed for awhile, it was called Coinhive. Each visitor would be treated like a node in a mining pool with “credit” for the resources going to the site owner. Somewhat predictably it became primarily used by hackers who would inject the code on high profile sites or use advertising networks. https://krebsonsecurity.com/2018/03/who-and-what-is-coinhive/ https://krebsonsecurity.com/2018/03/who-and-what-is-coinhive...
- xd1936 1y ago
  The domain is now owned by Troy Hunt! https://www.troyhunt.com/i-now-own-the-coinhive-domain-heres-how-im-fighting-cryptojacking-and-doing-good-things-with-content-security-policies/ https://www.troyhunt.com/i-now-own-the-coinhive-domain-heres...
SilasX 1y ago
From my understanding: to pose the problem for miners, you hash the block you're planning to submit (which includes all the proposed transactions). Miners only get the hash. To claim the reward, you need the preimage (i.e. block to be submitted), which miners don't have. In theory, you could watch the transactions being broadcast, and guess (+confirm) the corresponding block, but that would require you to see all the transactions the pool owner did, and put them in the same order (the possibilities of which scale exponentially with the number of transactions). There may be some other randomness you can insert into a block too -- someone else might know this. Edit: oops, I forgot: the block also contains the address that the fees should be sent to. So even if you "stole" your solution and broadcast it with the block, the fee is still going to the pool owner. That's a bigger deal.
deleted 1y ago
[deleted]
moralestapia 1y ago
Yeah, but then they wouldn't get your content? Duh.
csense 1y ago
> why shouldn't the visitor keep that proof to themselves and use it instead Because they can't, if the website operator designs their JavaScript correctly. In detail: If Alice goes to Bob's website, Bob tells Alice to find a hash with 20 leading zeros for a Bitcoin block that says "Send the newly printed bitcoins and transaction fees to Bob." (It will take Alice ~2^20 guesses to find such a block, so Bob picked the number 20 such that those ~2^20 guesses happen in a couple seconds for normal humans with normal web browsers on normal devices.) Supposing the actual Bitcoin blockchain needs a hash with 50 leading zeros, one in every 2^30 Alice's will mine a valid block (worth ~$300k at current Bitcoin prices). If Alice finds a block with 50 leading zeros and then tries to change the block to say "Send the newly printed bitcoins and transaction fees to Alice," her new block will have a different hash (that is very unlikely to have 2^50 leading zeros), and neither the website nor the blockchain will accept it. Sure, Alice could change the block at the beginning before starting the search. But if she finds a block with 20 leading zeros that says "Send the newly printed bitcoins and transaction fees to Alice," Bob won't accept it for access to his website. The only way Alice gets anything for a block that sends the coins to herself is from the Bitcoin blockchain if she finds a 2^50 block -- at that point, Alice is just mining Bitcoins for herself and not interacting with Bob's website at all. (If a 1 in a billion chance to win $300k is too risky for Bob's liking, he can get a lower payout with a higher probability by using a different proof-of-work blockchain and/or a mining pool.)

by diggan 1y ago

Retr0id 1y ago

If the user mined it themselves and then paid the site owner before accessing the site, they'd have to pay a transaction fee and wait for a high-latency transaction to commit. The transaction fee could dwarf the actual payment value. Mining on behalf of the site owner negates the need for a transaction entirely.

viraptor 1y ago
(unnecessary)
- Retr0id 1y ago
  I know this.
  - viraptor 1y ago
    Responded to wrong comment, sorry

odo1242 1y ago

The company Coinhive used to do this before they shut down. Basically, in order to enter a website, you have to provide the website with a certain number of Monero hashes (usually around 1,024) that the website would send to Coinhive’s miner pool before letting the user through. It kinda worked, except for the fact that hackers would try to “cryptojack” random websites by hacking them and inserting Coinhive’s miner into their pages. This caused everyone to block Coinhive’s servers. (Also you wouldn’t get very much money out of it - even the cryptojackers who managed to get tens of millions of page views out of hacked websites reported they only made ~$40 from the operation)

kbenson 1y ago
If attackers only made ~$40 fora good amount of work, seems like it would have resolved itself if the scheme was left to run itself to conclusion before people started blocking coinhive in (what sounds like from your description) a knee-jerk reaction. Then again, I'm sure there's quite a bit of tweaking that could be done to make clients submit far more hashes, but that would make it much more noticeable.
hoppp 1y ago
That $40 now coud be in the thousands if they didn't spend it Xmr was cheaper back then.

viraptor 1y ago

Have a look at how mining pools are implemented. The client only gets to change some part of the block and does the hashing from there. You can't go back from that to change the original data - you wouldn't get paid. Otherwise you could easily scam the mining pool and always keep the winning numbers to yourself while getting paid for the partials too.

mistercow 1y ago
Just to make sure I understand this (and maybe clarify for others too), because my understanding of proof-of-work systems is very high level: When you mine a block, you’re basically bundling up a bunch of meaningful data, and then trying to append some padding data that will e.g. result in a hash that has N leading 0 bits. One of the pieces of meaningful data in the block is “who gets the reward?” If you’re mining alone, you would put data on that block that says “me” as who gets the reward. But if you’re mining for a pool, you get a block that already says “the pool” for who gets the reward. So then I’m guessing the pool gives you a lesser work factor to hit, so some value smaller than N? You’ll be basically saying “Well, here’s a block that doesn’t have N leading zeroes, but does have M, leading zeroes”, and that proves how much you’re working for the pool, and entitles you to a proportion of the winnings. If you changed the “who gets the reward?” from “the pool” to “me”, that would change the hash. So you can’t come in after the fact, say “Look at that! N leading zeroes! Let me just swap myself in to get the reward…” because that would result in an invalid block. And if you put yourself as the reward line in advance, the pool just won’t give you credit for your “partial” answers. Is that about right?
- mistercow 1y ago
  Just to tack onto this, the one thing you could do is just deny real rewards. If someone wants you to take part in their pool in order to load a webpage, you could just refuse to submit any block that will actually pay out. This wouldn’t benefit you, but it would punish them for trying to make you spend resources on their behalf. I wonder if there’s a way to prevent that.

lurkshark 1y ago

This system actually existed for awhile, it was called Coinhive. Each visitor would be treated like a node in a mining pool with “credit” for the resources going to the site owner. Somewhat predictably it became primarily used by hackers who would inject the code on high profile sites or use advertising networks. https://krebsonsecurity.com/2018/03/who-and-what-is-coinhive/ https://krebsonsecurity.com/2018/03/who-and-what-is-coinhive...

xd1936 1y ago
The domain is now owned by Troy Hunt! https://www.troyhunt.com/i-now-own-the-coinhive-domain-heres-how-im-fighting-cryptojacking-and-doing-good-things-with-content-security-policies/ https://www.troyhunt.com/i-now-own-the-coinhive-domain-heres...

SilasX 1y ago

From my understanding: to pose the problem for miners, you hash the block you're planning to submit (which includes all the proposed transactions). Miners only get the hash. To claim the reward, you need the preimage (i.e. block to be submitted), which miners don't have. In theory, you could watch the transactions being broadcast, and guess (+confirm) the corresponding block, but that would require you to see all the transactions the pool owner did, and put them in the same order (the possibilities of which scale exponentially with the number of transactions). There may be some other randomness you can insert into a block too -- someone else might know this. Edit: oops, I forgot: the block also contains the address that the fees should be sent to. So even if you "stole" your solution and broadcast it with the block, the fee is still going to the pool owner. That's a bigger deal.

deleted 1y ago

[deleted]

moralestapia 1y ago

Yeah, but then they wouldn't get your content? Duh.

csense 1y ago

> why shouldn't the visitor keep that proof to themselves and use it instead Because they can't, if the website operator designs their JavaScript correctly. In detail: If Alice goes to Bob's website, Bob tells Alice to find a hash with 20 leading zeros for a Bitcoin block that says "Send the newly printed bitcoins and transaction fees to Bob." (It will take Alice ~2^20 guesses to find such a block, so Bob picked the number 20 such that those ~2^20 guesses happen in a couple seconds for normal humans with normal web browsers on normal devices.) Supposing the actual Bitcoin blockchain needs a hash with 50 leading zeros, one in every 2^30 Alice's will mine a valid block (worth ~$300k at current Bitcoin prices). If Alice finds a block with 50 leading zeros and then tries to change the block to say "Send the newly printed bitcoins and transaction fees to Alice," her new block will have a different hash (that is very unlikely to have 2^50 leading zeros), and neither the website nor the blockchain will accept it. Sure, Alice could change the block at the beginning before starting the search. But if she finds a block with 20 leading zeros that says "Send the newly printed bitcoins and transaction fees to Alice," Bob won't accept it for access to his website. The only way Alice gets anything for a block that sends the coins to herself is from the Bitcoin blockchain if she finds a 2^50 block -- at that point, Alice is just mining Bitcoins for herself and not interacting with Bob's website at all. (If a 1 in a billion chance to win $300k is too risky for Bob's liking, he can get a lower payout with a higher probability by using a different proof-of-work blockchain and/or a mining pool.)