We can confirm that there was a successful 51% attack on Ethereum Classic • Hacker News Board

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#81

Post by jonahx » Mon, Jan 07, 2019, 11:04 PM UTC

CydeWeys wrote: post #40

johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

If you're not on the largest coin for any particular interchangeable hashing algorithm then you're susceptible to these attacks, as people from a larger coin could simply turn their hardware against you and take you out. That means: For SHA256^2-specific hardware, Bitcoin (the real one, not Cash, Gold, or SV), for scrypt, Litecoin, and for anything mined on GPUs, Ethereum (not Classic).

Would you mind elaborating on this for someone unfamiliar?

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#82

Post by tokai » Mon, Jan 07, 2019, 11:04 PM UTC

danra wrote: post #65

johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

Really surprised by the relatively low cost of attacking Bitcoin with 51% for one hour - claimed to be about $300k. Is this number for real? I can think of many actors for whom this is just small change, and who might have incentive to break trust in the Bitcoin network by successfully performing such an attack.

That is a really low cost. That's within crowdfunding territory. If a potato salad could make it big, why not fund a major event in web history? I'm thinking stretch goals like t-shirts and mugs.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#83

Post by [deleted] » Mon, Jan 07, 2019, 11:04 PM UTC

sp332 wrote: post #69

CydeWeys wrote: post #40

Earlier quoted context omitted.

If you're not on the largest coin for any particular interchangeable hashing algorithm then you're susceptible to these attacks, as people from a larger coin could simply turn their hardware against you and take you out. That means: For SHA256^2-specific hardware, Bitcoin (the real one, not Cash, Gold, or SV), for scrypt, Litecoin, and for anything mined on GPUs, Ethereum (not Classic).

people from a larger coin could simply turn their hardware against you and take you out. Only at the expense of leaving their coin more vulnerable to a similar attack.

[deleted]

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#84

Post by matte_black » Mon, Jan 07, 2019, 11:10 PM UTC

brianwawok wrote: post #23

NathanCH wrote: post #18

Earlier quoted context omitted.

Some of these numbers are very low. $30/h for Bitcoin Private? Seems inexpensive, what am I missing?

No one uses it. So you attack it. Cool. You can't turn it into USD or anything else, so you just spend $30 for nothing.

But you still get the prestige of having taken down a coin.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#85

Post by hinkley » Mon, Jan 07, 2019, 11:12 PM UTC

I think I would be satisfied with the distributed consensus model in these blockchain systems if someone could solve the non-repudiation problem.

In many of these blockchain systems, the 51% attacks only applies to money in motion. I can't move all of your funds out of 'your account' unless I have stolen your wallet, and if I have stolen your wallet I don't need to change anything else about the network. I can just spend on your behalf.

Lacking that, I can convince you you got paid for services and then claw them back by making the network change their mind after the fact. I can repudiate all payments to you with a 51% attack, by voting again on what transactions just finished.

Congress has rules about votes. If you have a quorum, everybody sticks with the outcome. If you don't show up, you don't get a vote. To make that work, you have rules. A quorum is defined and static. Obstruction is not allowed - no secret votes, no locking the doors.

It may be as simple as this: When my transaction is settled I need to know the health of the system. If some definition of quorum is met I know my transaction can't be hijacked. If the network was degraded a revote is possible. I need to wait for more confirmation before rendering services.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#86

Post by WalterSear » Mon, Jan 07, 2019, 11:13 PM UTC

CydeWeys wrote: post #40

johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

If you're not on the largest coin for any particular interchangeable hashing algorithm then you're susceptible to these attacks, as people from a larger coin could simply turn their hardware against you and take you out. That means: For SHA256^2-specific hardware, Bitcoin (the real one, not Cash, Gold, or SV), for scrypt, Litecoin, and for anything mined on GPUs, Ethereum (not Classic).

Hooray decentralization!

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#87

Post by root_axis » Mon, Jan 07, 2019, 11:13 PM UTC

Klathmon wrote: post #71

theamk wrote: post #54

Earlier quoted context omitted.

... It's great when you can lose lots of money by spilling soda on your computer?* *more money than this computer's price

can we not do this here please? Nobody wants that, nobody is saying they want that, there are mitigations against that (like backups), and it's a stupid straw man that's not even trying to engage in a meaningful conversation on the topic.

Nobody wants to back up their money. Just use a bank and never worry about it.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#88

Post by baddox » Mon, Jan 07, 2019, 11:14 PM UTC

danra wrote: post #65

johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

Really surprised by the relatively low cost of attacking Bitcoin with 51% for one hour - claimed to be about $300k. Is this number for real? I can think of many actors for whom this is just small change, and who might have incentive to break trust in the Bitcoin network by successfully performing such an attack.

Seems like it would be very difficult to make back your $300k with a double-spend in one hour, based both on my intuition and the fact that it doesn't appear to be happening.

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#89

Post by baddox » Mon, Jan 07, 2019, 11:16 PM UTC

matte_black wrote: post #84

brianwawok wrote: post #23

Earlier quoted context omitted.

No one uses it. So you attack it. Cool. You can't turn it into USD or anything else, so you just spend $30 for nothing.

But you still get the prestige of having taken down a coin.

What makes you think there would be any such prestige earned?

Re: We can confirm that there was a successful 51% attack on Ethereum Classic

#90

Post by [deleted] » Mon, Jan 07, 2019, 11:18 PM UTC

danra wrote: post #65

johndunne wrote: post #7

This is inevitable. Ethereum Classic (ETC) isn't the only currency such attacks have been successful on. The site https://www.crypto51.app/ puts the cost of running a 51% attack on ETC at ~$5k per hour. The incentive for running these attacks for profit becomes higher as the market cap of these coins increases, making long-term 'investment' in these coins nonsensical.

Really surprised by the relatively low cost of attacking Bitcoin with 51% for one hour - claimed to be about $300k. Is this number for real? I can think of many actors for whom this is just small change, and who might have incentive to break trust in the Bitcoin network by successfully performing such an attack.

[deleted]