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Cost of a 51% attack for different cryptocurrencies?

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Re: Cost of a 51% attack for different cryptocurrencies?

#91

Post by EthanHeilman »

SilasX wrote: post #78
RL_Quine wrote: post #68

Earlier quoted context omitted.

Why are you assuming that hashrate would be obtained legally? If you're already assuming criminality, go all out! BGP route hijack the unencrypted, unauthenticated mining traffic and call it your own. Cost is basically nothing to do so, other than some jail time.

Can you clarify what you mean by hijacking mining traffic? If you mean the traffic of mining pools communicating their solutions to the pool's "mother brain", those are already cryptographically attached to a solution that pays out to specified addresses. You can't substitute the transactions in the block/solution without redoing the PoW. That's why miners can't steal a pool's solutions to begin with.

Poster is probably referencing this BGP attack on a mining pool.

"BGP Hijacking for Cryptocurrency Profit" - https://www.secureworks.com/research/bgp-hijacking-for-crypt...

An attack like this could be repurposed to perform reorgs with 51% of the mining power as the stratum pool server decides what previous block to mine on. No idea if mining pools or the stratum protocol has added countermeasures to prevent such an attack in the future.

Re: Cost of a 51% attack for different cryptocurrencies?

#92

Post by RL_Quine »

bufferoverflow wrote: post #90
RL_Quine wrote: post #68

Earlier quoted context omitted.

Why are you assuming that hashrate would be obtained legally? If you're already assuming criminality, go all out! BGP route hijack the unencrypted, unauthenticated mining traffic and call it your own. Cost is basically nothing to do so, other than some jail time.

That's not how any of this works. There's no massive mining traffic. Most of the mining is done in private data centers. They only broadcast their transactions when they "solve" the hash.

This is exactly how it works! Most miners are connected to pools like slushpool, f2pool, etc over unencrypted an unauthenticated links. If you can modify this traffic you can steal the hashrate, because you can modify the work being sent to the miners before they do any hashing.

Re: Cost of a 51% attack for different cryptocurrencies?

#93

Post by aphextim »

RL_Quine wrote: post #84
SilasX wrote: post #78

Earlier quoted context omitted.

Can you clarify what you mean by hijacking mining traffic? If you mean the traffic of mining pools communicating their solutions to the pool's "mother brain", those are already cryptographically attached to a solution that pays out to specified addresses. You can't substitute the transactions in the block/solution without redoing the PoW. That's why miners can't steal a pool's solutions to begin with.

All miners connect to pools using a protocol called stratum. This is JSON piped over TCP with newline terminations. There is no authentication for this protocol and no encryption. You can simply intercept the communication here and have all the miners on a pool actually mine for your replacement pool, and nobody will ever catch on until its far too late. > If you mean the traffic of mining pools communicating their s…

When I was toying around with mining some alt coins with GPUs a few years back I had the thought when joining a mining pool on say supernova, what is to prevent someone from doing an attack and convincing the pool to send my coins to them instead at a level 'under the hood' and beyond my understanding. Or get the entire pool to act in a way that is for their own personal gain.

I know there had been guides on how to set up your mining rigs, setup the batch files etc. These were all guides written by other people and I could see how in this newly created space there was room for nefarious actors to try to convince people to mine in a pool, but not give them the rewards they deserved or scammed them in some other way.

I also thought about someone hacking entire pools' hash-rates to be used for their own purposes rather than trying to figure out the next block on whatever chain it was running. This would allow someone to 'steal' the hash power of expensive rigs and redirect the power to their own wallets.

My understanding of all these protocols is very limited to what is regurgitated from others. When it comes to reading the bitcoin whitepaper I was only able to comprehend up until section 11 on page 6 where it got into the calculations, at which point I got lost as I am not that good at math.

Thank you for the insight.

Re: Cost of a 51% attack for different cryptocurrencies?

#94

Post by EthanHeilman »

bufferoverflow wrote: post #90
RL_Quine wrote: post #68

Earlier quoted context omitted.

Why are you assuming that hashrate would be obtained legally? If you're already assuming criminality, go all out! BGP route hijack the unencrypted, unauthenticated mining traffic and call it your own. Cost is basically nothing to do so, other than some jail time.

That's not how any of this works. There's no massive mining traffic. Most of the mining is done in private data centers. They only broadcast their transactions when they "solve" the hash.

These private mining datacenters typically get their block templates from pool servers. Miners communicate with the pool servers over the internet. Control the pool server control the mining power.

Re: Cost of a 51% attack for different cryptocurrencies?

#95

Post by hudon »

qertoip wrote: post #72
hudon wrote: post #34

If you're capable of playing a long con, it costs much less than the stated dollar prices. With Bitcoin, for example, a smart malicious actor could infiltrate the Core development team and through their social capital make certain malicious pull requests get merged. This way, if the chain ever splits (let's say, due to a bug you planted), you can actually also influence miners to hop onto a minor chain without you ev…

The double spend is only possible against specific counter-party, for example an exchange or a merchant. For very large value transfers exchanges are expected to wait for 100 confirmations (~17 hours) until they credit balance. It's all probabilistic. Finally, Bitcoin PoW is not security theatre, it is just one piece of the complex security system.

The most recent bug (that we know of) that allowed double-spend was in production for over a year [0] (~Sept 2017 to ~Sept 2018). I don't think it is possible to accurately determine the probability of this bug being exploited (because you are right, it is "all probabilistic"), but this inability to determine the probabilities is precisely why PoW is security theatre. PoW has always been painted as a mathematical model of the security of the system (see featured article), but in reality this model is not accounting for the much more realistic attack vectors. Hence it fails to be an accurate model.

If you're just saying that PoW isn't painting the whole picture, I agree with you.

[0] https://bitcoincore.org/en/2018/09/20/notice/

Re: Cost of a 51% attack for different cryptocurrencies?

#96

Post by RL_Quine »

EthanHeilman wrote: post #91
SilasX wrote: post #78

Earlier quoted context omitted.

Can you clarify what you mean by hijacking mining traffic? If you mean the traffic of mining pools communicating their solutions to the pool's "mother brain", those are already cryptographically attached to a solution that pays out to specified addresses. You can't substitute the transactions in the block/solution without redoing the PoW. That's why miners can't steal a pool's solutions to begin with.

Poster is probably referencing this BGP attack on a mining pool. "BGP Hijacking for Cryptocurrency Profit" - https://www.secureworks.com/research/bgp-hijacking-for-crypt... An attack like this could be repurposed to perform reorgs with 51% of the mining power as the stratum pool server decides what previous block to mine on. No idea if mining pools or the stratum protocol has added countermeasures to prevent such an…

> No idea if mining pools or the stratum protocol has added countermeasures to prevent such an attack in the future.

Not really. There's some discussion about Stratum2 having stronger authentication, and systems like BetterHash to take away a lot of the centralizing impacts of pools by having people create their own work, and only centralizing the payouts for that work. It's a bit of a challenge because there's such a huge range of hardware out there with incomplete implementations of stratum in closed source forks of mining software. You basically have to wait for it to just be obsolete and replaced because there will never be updates.

Re: Cost of a 51% attack for different cryptocurrencies?

#97

Post by [deleted] »

RL_Quine wrote: post #96
EthanHeilman wrote: post #91

Earlier quoted context omitted.

Poster is probably referencing this BGP attack on a mining pool. "BGP Hijacking for Cryptocurrency Profit" - https://www.secureworks.com/research/bgp-hijacking-for-crypt... An attack like this could be repurposed to perform reorgs with 51% of the mining power as the stratum pool server decides what previous block to mine on. No idea if mining pools or the stratum protocol has added countermeasures to prevent such an…

> No idea if mining pools or the stratum protocol has added countermeasures to prevent such an attack in the future. Not really. There's some discussion about Stratum2 having stronger authentication, and systems like BetterHash to take away a lot of the centralizing impacts of pools by having people create their own work, and only centralizing the payouts for that work. It's a bit of a challenge because there's such…

[deleted]

Re: Cost of a 51% attack for different cryptocurrencies?

#98

Post by Forbo »

RL_Quine wrote: post #81
seibelj wrote: post #47

Earlier quoted context omitted.

There are no ASICs known to work on Monero anymore. As a brief summary, the new algorithm (RandomX) uses a bespoke virtual machine that requires 2GB of memory, and programs are randomly generated until the opcodes take in an input (previous block hash) and have an output (new hash with required difficulty) that pass the requirements. It is very interesting. https://github.com/tevador/RandomX

A GPU is an ASIC, which can mine RandomX. The idea that you could make something that's able to only be computed by a general purpose GPU, and not something more specialized, is just absurd. Even if that's just removing the unnecessary display hardware from the GPU and whatever parts of the shaders aren't being used, you still have an advantage.

GPUs actually have a significant disadvantage on RandomX. Their hashrate is much lower than what you'd get from a CPU.

Edit for more info:

https://monerobenchmarks.info/

According to this site, an overclocked Titan RTX gets about the same hash rate as a stock AMD FX8370E at nearly half the TDP.

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