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Re:Hard Problems in Cryptocurrency: Five Years Later by jkhdigital on Sunday November 24, 2019 @12:20AM (#21618544)
So glad you asked:

1. https://eprint.iacr.org/2019/748.pdf 2. https://arxiv.org/pdf/1810.11605.pdf 3. https://eprint.iacr.org/2019/775.pdf 4. https://users.encs.concordia.ca/~clark/papers/2019_wtsc_fron... 5. 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

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

Re:Hard Problems in Cryptocurrency: Five Years Later by hanniabu on Sunday November 24, 2019 @05:41AM (#21619563)
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.
Re:Hard Problems in Cryptocurrency: Five Years Later by jotakami on Sunday November 24, 2019 @08:28AM (#21620277)
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?

Re:Hard Problems in Cryptocurrency: Five Years Later by hanniabu on Sunday November 24, 2019 @12:08PM (#21621700)
I do understand. I work in the industry, specifically with decentralized exchanges. Both the order book and the order matching should be P2P with 0 conf transactions and client side verification. The fees paid by the user should be top off fees for the contract balance rather than pay to play fees.
Re:Hard Problems in Cryptocurrency: Five Years Later by semiotagonal on Sunday November 24, 2019 @10:59AM (#21621151)
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.
Re:Hard Problems in Cryptocurrency: Five Years Later by alanfalcon on Sunday November 24, 2019 @11:18AM (#21621308)
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!)

Re:Hard Problems in Cryptocurrency: Five Years Later by exdsq on Sunday November 24, 2019 @01:14PM (#21622184)
I completely agree! It's sparked an interest in formal methods and learning more about how engineering takes place in other disciplines to improve their product quality.
Re:Hard Problems in Cryptocurrency: Five Years Later by semiotagonal on Sunday November 24, 2019 @12:05PM (#21621673)
Learning on the job in an unforgiving domain can be costly.
Re:Hard Problems in Cryptocurrency: Five Years Later by alanfalcon on Sunday November 24, 2019 @02:46PM (#21622815)
The blockchain is indeed fraught with peril. Code review, audits, and bug bounties are an absolute necessity when it comes to smart contracts! Learning in a high stakes situation seems pretty good as long as you have a robust support structure.
Re:Hard Problems in Cryptocurrency: Five Years Later by neiman on Sunday November 24, 2019 @03:39AM (#21619167)
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.

Re:Hard Problems in Cryptocurrency: Five Years Later by jotakami on Sunday November 24, 2019 @08:46AM (#21620368)
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.