4 ms·

So glad you asked: 1. https://eprint.iacr.org/2019/748.pdf https://eprint.iacr.org/2019/748.pdf 2. https://arxiv.org/pdf/1810.11605.pdf https://arxiv.org/pdf/1

So glad you asked: 1. https://eprint.iacr.org/2019/748.pdf https://eprint.iacr.org/2019/748.pdf 2. https://arxiv.org/pdf/1810.11605.pdf https://arxiv.org/pdf/1810.11605.pdf 3. https://eprint.iacr.org/2019/775.pdf https://eprint.iacr.org/2019/775.pdf 4. https://users.encs.concordia.ca/~clark/papers/2019_wtsc_front.pdf https://users.encs.concordia.ca/~clark/papers/2019_wtsc_fron... 5. http://homepages.cs.ncl.ac.uk/patrick.mccorry/minerbribery.pdf http://homepages.cs.ncl.ac.uk/patrick.mccorry/minerbribery.p... This one isn't an attack per se, it is mostly an exploration of arbitrage bots in decentralized exchanges running on Ethereum smart contracts. However, they point out that miners can trivially capture the value of the arbitrage transactions by front-running, and that this "free money" is like a bonus block subsidy that falls outside of the PoW consensus models: 6. https://arxiv.org/pdf/1904.05234.pdf https://arxiv.org/pdf/1904.05234.pdf This one actually operates through transaction fees only, so it doesn't depend on smart contract functionality. However, it is waaaaay more expensive (for the attacker) than the others: 7. https://www.cs.umd.edu/~jkatz/papers/whale-txs.pdf https://www.cs.umd.edu/~jkatz/papers/whale-txs.pdf

neiman 7y ago
I haven't read all those papers, but basically you could always bribe miners, even without smart contracts, just by giving them money outside the blockchain they mine. One of the ideas of PoW is that if you have enough money to bribe the miners, it's better for you to be a miner yourself. Is this the principle your examples weakens? I may have misinterpreted them.
- jotakami 7y ago
  Bribing outside of the system (i.e. in real life) could be a tremendous coordination and logistical challenge, especially given the amounts needed to make these attacks profitable. Smart contracts can make all of that trivially easy. It’s like... the people most interested in trustless collaboration are people who are untrustworthy. A trustless settlement layer seems fine, but any real human application is going to have an element of trust and doesn’t belong alongside settlement.
hanniabu 7y ago
You're using a poor implementation of an app as a reason why smart contracts are bad. I hope you realize this is the same thing as saying databases are bad because of the Equifax hack.
- jotakami 7y ago
  I don’t think you understand. The arbitrage bots aren’t exploiting poorly written contracts, they are capturing free value that users of a dApp have opened up. This free value is available to miners as well, and could be used to subsidize an otherwise-unprofitable double spend attack. But more to the point: allowing smart contracts in a blockchain introduces all of the complexity of trying to make any other piece of software secure. Except... now it’s on a blockchain where the code is open source and mistakes can allow adversaries to steal money, not just data. How is this an improvement?
  - semiotagonal 7y ago
    I did about 0.1% of the amount of research you did a few years ago and was really struck by the irreversibility of mistakes. Other engineering domains can have irreversible (e.g. fatal) mistakes as well, but they don't have as many enthusiasts jumping in to the field.
    - alanfalcon 7y ago
      Our CTO likens developing a smart contract to civil engineering. Our CTO also remembers what it was like to ship your software in its final form on a floppy disk! I think it’s great that more and more people are jumping in and learning what it’s like to develop in such an unforgiving domain (no point here, I just think it’s great!)
      - semiotagonal 7y ago
        Learning on the job in an unforgiving domain can be costly.

neiman 7y ago

I haven't read all those papers, but basically you could always bribe miners, even without smart contracts, just by giving them money outside the blockchain they mine. One of the ideas of PoW is that if you have enough money to bribe the miners, it's better for you to be a miner yourself. Is this the principle your examples weakens? I may have misinterpreted them.

jotakami 7y ago
Bribing outside of the system (i.e. in real life) could be a tremendous coordination and logistical challenge, especially given the amounts needed to make these attacks profitable. Smart contracts can make all of that trivially easy. It’s like... the people most interested in trustless collaboration are people who are untrustworthy. A trustless settlement layer seems fine, but any real human application is going to have an element of trust and doesn’t belong alongside settlement.

hanniabu 7y ago

You're using a poor implementation of an app as a reason why smart contracts are bad. I hope you realize this is the same thing as saying databases are bad because of the Equifax hack.

jotakami 7y ago
I don’t think you understand. The arbitrage bots aren’t exploiting poorly written contracts, they are capturing free value that users of a dApp have opened up. This free value is available to miners as well, and could be used to subsidize an otherwise-unprofitable double spend attack. But more to the point: allowing smart contracts in a blockchain introduces all of the complexity of trying to make any other piece of software secure. Except... now it’s on a blockchain where the code is open source and mistakes can allow adversaries to steal money, not just data. How is this an improvement?
- semiotagonal 7y ago
  I did about 0.1% of the amount of research you did a few years ago and was really struck by the irreversibility of mistakes. Other engineering domains can have irreversible (e.g. fatal) mistakes as well, but they don't have as many enthusiasts jumping in to the field.
  - alanfalcon 7y ago
    Our CTO likens developing a smart contract to civil engineering. Our CTO also remembers what it was like to ship your software in its final form on a floppy disk! I think it’s great that more and more people are jumping in and learning what it’s like to develop in such an unforgiving domain (no point here, I just think it’s great!)
    - semiotagonal 7y ago
      Learning on the job in an unforgiving domain can be costly.