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Comment by samfisher83 | Hacker News Reader

Why is og bitcoin not on the list?

You can't rent that algorithm on the market they are calculating the spot rates for this from; you can come at this in another direction by asking "how much profit would I have to buy off of someone else to convince them to lend me their mining equipment", and we could quibble over whether that would provide more accurate results (I think it would), but I appreciate where the author of this site is coming from: this is how much it might cost to rent this much power off an existing open market for algorithms (which doesn't bother with Bitcoin as that is mined with specialized hardware and this kind of spot market doesn't apply very well).

That's not accurate. You can definitely buy hashing power for BTC on NiceHash[1]. Bitcoin is just SHA-256. The more likely explanation (given that this is the crypto space) is that the author is a BTC bagholder.

[1] https://www.nicehash.com/my/marketplace/SHA256

Bitcoin equipment is specilaised to mining. You'd have to rent 51% of all mining eqipment for an attack, at which point you wouod destroy the value of bitcoin and make the mining eqipment you've just rented worthless. Why would anyone rent to you in that case?

So you'd have to buy the equipment, which is a gradual process, would be extremely expensive and would be noticed.

Bitcoin uses a SHA-256 hash algo, you definitely don't need specialized hardware to compute SHA-256 hashes. Yes, the competitive miners have ASICs which get you many more hashes per joule, but you can definitely rent hashing power that could 51% attack BTC without renting ASICs, it would just cost you more than if you could easily rent the most competitive hardware (obviously).

Its also more hashes per $1. If you are renting general purpose compute to beat ASIC compute you will need like 50x advantage. That's probably more than a single AWS datacenter can provide

I don't disagree, but the idea that you can't use the same methodology to determine a 51% attack price for Bitcoin is just wrong.

Indeed, back-of-the-napkin calculation with an order randomly picked from NiceHash[1] for Bitcoin mining and the same methodology gives:

Cost (PH/HR): 0.0002625 BTC

Bitcoin Network Hashrate (PH/HR): 9M

51% attack for one hour: 4.6M PH => 4.6M * 0.0002625 ~= 1200 BTC

So a one-hour long 51% on the bitcoin network would cost $43,200,000 at $36K per BTC, as per a NiceHash rate I randomly selected.

[1] https://www.nicehash.com/my/marketplace/SHA256

But that number is super misleading - you cant actually get that much compute from nicehash, you would struggle to get that much compute even from aws.

You real costs are going to be much higher, it would probably take you more than an hour to spin it all up and execute the attack. I feel realistic number is 10x to 100x higher

Right, you can't get to 51% of the Ethereum network with NiceHash either, but it's still on this website, so...?

Destroying the value of Bitcoin seems like a nation-backed attack on cryptocurrency that at least a few countries might benefit from.

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