Show HN: Cost of a 51% Attack on Popular Cryptocurrencies
Doing a 51% attack on a major coin, and actually profiting from it, is much more complicated than this chart implies. Here are some of the problems you&#x27;ll run into:<p>1. NiceHash doesn&#x27;t have anything like the hashpower you need to attack a major coin such as BTC or ETH. The chart admits that NiceHash has only 2% of the capacity you need to accomplish this on Bitcoin. You&#x27;ll need to start buying ASIC hardware or graphics cards to cover the other 98%. Both of those are hard to obtain in very large quantities quickly.<p>2. Since you have to buy the hardware, you can expect to pay much more than the NiceHash prices imply. Bitmain is one of the major suppliers of such hardware, so let&#x27;s use their prices as an example. One of their top Bitcoin ASICs is a 14 TH&#x2F;s unit that costs about $1,000 [1]. So you need about 2.5 million of these units at a cost of 2.5 billion dollars. Not that Bitmain has the capacity to fill such an order.<p>3. The cost of those ASICs is just the beginning. Have you seen photos of those Chinese data centers that have racks of mining ASICs on shelves? Each of those data centers has maybe a few percent of Bitcoin&#x27;s hash rate, so you&#x27;ll need to build something at least 30x larger. Your electric bill alone will exceed the GDP of some small countries. Since you&#x27;ve already spent billions of dollars on ASICs, hopefully you have some money left to pay it and hire a data center ops team.<p>4. How fast can you build all this out? Bitcoin&#x27;s hash rate has grown 30% over the last month[2]. You might sink billions of dollars into this project only to discover that you&#x27;ve come up short.<p>5. Congratulations, you can now make a few million dollars by 51% attacking the blockchain. You would, for example, deposit some bitcoins with a bunch of exchanges, sell them, withdraw dollars, and then use your hashpower to unwind those deposits and put the bitcoins back into your own wallet. It&#x27;ll take a few hours (or less) for every exchange to notice what you&#x27;re doing and freeze withdrawals. The bitcoin price will free-fall as everyone wonders about how to prevent this next time. You may or may not be arrested and charged with wire fraud. You&#x27;re done!<p>[1] <a href="https:&#x2F;&#x2F;shop.bitmain.com&#x2F;product&#x2F;detail?pid=00020180523201006625r2KQCnC10650" rel="nofollow">https:&#x2F;&#x2F;shop.bitmain.com&#x2F;product&#x2F;detail?pid=0002018052320100...</a>
[2] <a href="https:&#x2F;&#x2F;blockchain.info&#x2F;charts&#x2F;hash-rate" rel="nofollow">https:&#x2F;&#x2F;blockchain.info&#x2F;charts&#x2F;hash-rate</a>