5 ms·

Repurpose it how? You'd need ASICs to mount a 51% attack. Using a few quickly googled numbers, you'd need ~56EH/s to double the network and mount a 51% attack.

Repurpose it how? You'd need ASICs to mount a 51% attack. Using a few quickly googled numbers, you'd need ~56EH/s to double the network and mount a 51% attack. An S9 does 14TH/s, so you'd need ~4 million, at $3k each. So around $12 billion (plus the datacenter, operations, etc). You'd pretty much send BTC to being worth $0...and then you're stuck with $12 billion in useless hardware.

lmpostor 7y ago
94EH and close to 50TH for top of the line equipment. Even if we were extremely generous would be a billion in hardware at the very least (I am assuming $500 manufacturing cost)
- qroshan 7y ago
  The Market Cap of Bitcoin is $184,000,000,000 Theoretically, I can spend that much to make it's value go to $0. (yes, there are liquidity and other concerns, but you get the point)
  - arthurcolle 7y ago
    No, you couldn't because you'd need to borrow the entire float, which is impossible, practically and theoretically.
qroshan 7y ago
If my goal is to re-purpose, I would use a General Purpose Computer The Market Cap of Bitcoin is $184,000,000,000 I have plenty of money to play with.
- nybble41 7y ago
  If your plan is to use general-purpose computers for mining then Bitcoin has nothing to worry about. You'll never manage a 51% attack that way, no when all your competition is using ASICs. Moreover, to gain $184B by shorting Bitcoin you'd need to find someone willing to loan you $184B worth of Bitcoin, and then somehow sell all of it without crashing the price or drawing unwanted attention to your activities. Of course if the price doesn't react the way you expect you could end up paying a lot more than $184B to buy it all back to repay the loan. You shouldn't assume that even a successful (but expensive, and obviously temporary) 51% attack will drive the price down to zero.
  - qroshan 7y ago
    It all depends on who is doing the attacking. If the attacker is a state government or someone with billions of dollars and compute to spare, ASICs aren't going to fight this losing battle. Heck, you can buy off the ASIC miners for a few million dollars (all we have to cover is their net profit, which is pretty low)
    - kragen 7y ago
      The cost of mounting the attack with general-purpose computers would be orders of magnitude higher than the US$12B calculated above, just from the energy bill. Check out https://en.bitcoin.it/wiki/Mining_hardware_comparison; https://en.bitcoin.it/wiki/Mining_hardware_comparison; the ASIC AntMiner S9 gets 10 billion hashes per joule, while on https://en.bitcoin.it/wiki/Non-specialized_hardware_comparison https://en.bitcoin.it/wiki/Non-specialized_hardware_comparis... you can see that the most efficient GPUs get 2–3 million hashes per joule, 3000 to 5000 times less. So instead of spending US$12 billion on hardware and US$4 billion per year on power, you'd be spending US$12 trillion per year on power. No state has such a large budget; that's more than half of the US GDP, and about 15% of world GDP. That's more than the amount of marketed energy produced in the world. That is, the attack you're proposing would require commandeering 15% of the world economy and more than doubling world electrical generation capacity. Bribing or backdooring ASIC miners is a far more likely vulnerability.
      - lonelappde 7y ago
        Are ASICs totally useless for non Bitcoin computing?
        kragen 7y ago
        Yes, that's what the “AS” stands for.
        mikekchar 7y ago
        To be a bit more specific, the ASIC is a computation built in hardware. It can do that computation and that computation alone. The algorithm in Bitcoin does absolutely nothing useful -- you are just hashing a random number and seeing if the result is below a certain value. Since you can't change the computation on the ASIC, it's absolutely useless for anything except mining bitcoins.
aiCeivi9 7y ago
Can anybody explain to me why would anybody try to make their alt-coin ASIC-resistant? They claim it is do decrease centralization but like parent says it just makes 51% attack possible with cloud computing and 0 investment in hardware or logistics.
- tempay 7y ago
  The issue with ASIC mining is the the barrier to entry is extremely high so only a small number of people have the means to produce the chips. Economically it might not make sense to sell them and, to make the situation even worse, patents can prevent competitors being able to use the same innovations.
- imtringued 7y ago
  The first ASIC company can just keep the ASICs for themselves.
qaq 7y ago
Well aren't there BTC futures on CME?

lmpostor 7y ago

94EH and close to 50TH for top of the line equipment. Even if we were extremely generous would be a billion in hardware at the very least (I am assuming $500 manufacturing cost)

qroshan 7y ago
The Market Cap of Bitcoin is $184,000,000,000 Theoretically, I can spend that much to make it's value go to $0. (yes, there are liquidity and other concerns, but you get the point)
- arthurcolle 7y ago
  No, you couldn't because you'd need to borrow the entire float, which is impossible, practically and theoretically.

qroshan 7y ago

If my goal is to re-purpose, I would use a General Purpose Computer The Market Cap of Bitcoin is $184,000,000,000 I have plenty of money to play with.

nybble41 7y ago
If your plan is to use general-purpose computers for mining then Bitcoin has nothing to worry about. You'll never manage a 51% attack that way, no when all your competition is using ASICs. Moreover, to gain $184B by shorting Bitcoin you'd need to find someone willing to loan you $184B worth of Bitcoin, and then somehow sell all of it without crashing the price or drawing unwanted attention to your activities. Of course if the price doesn't react the way you expect you could end up paying a lot more than $184B to buy it all back to repay the loan. You shouldn't assume that even a successful (but expensive, and obviously temporary) 51% attack will drive the price down to zero.
- qroshan 7y ago
  It all depends on who is doing the attacking. If the attacker is a state government or someone with billions of dollars and compute to spare, ASICs aren't going to fight this losing battle. Heck, you can buy off the ASIC miners for a few million dollars (all we have to cover is their net profit, which is pretty low)
  - kragen 7y ago
    The cost of mounting the attack with general-purpose computers would be orders of magnitude higher than the US$12B calculated above, just from the energy bill. Check out https://en.bitcoin.it/wiki/Mining_hardware_comparison; https://en.bitcoin.it/wiki/Mining_hardware_comparison; the ASIC AntMiner S9 gets 10 billion hashes per joule, while on https://en.bitcoin.it/wiki/Non-specialized_hardware_comparison https://en.bitcoin.it/wiki/Non-specialized_hardware_comparis... you can see that the most efficient GPUs get 2–3 million hashes per joule, 3000 to 5000 times less. So instead of spending US$12 billion on hardware and US$4 billion per year on power, you'd be spending US$12 trillion per year on power. No state has such a large budget; that's more than half of the US GDP, and about 15% of world GDP. That's more than the amount of marketed energy produced in the world. That is, the attack you're proposing would require commandeering 15% of the world economy and more than doubling world electrical generation capacity. Bribing or backdooring ASIC miners is a far more likely vulnerability.
    - lonelappde 7y ago
      Are ASICs totally useless for non Bitcoin computing?
      - kragen 7y ago
        Yes, that's what the “AS” stands for.
        mikekchar 7y ago
        To be a bit more specific, the ASIC is a computation built in hardware. It can do that computation and that computation alone. The algorithm in Bitcoin does absolutely nothing useful -- you are just hashing a random number and seeing if the result is below a certain value. Since you can't change the computation on the ASIC, it's absolutely useless for anything except mining bitcoins.

aiCeivi9 7y ago

Can anybody explain to me why would anybody try to make their alt-coin ASIC-resistant? They claim it is do decrease centralization but like parent says it just makes 51% attack possible with cloud computing and 0 investment in hardware or logistics.

tempay 7y ago
The issue with ASIC mining is the the barrier to entry is extremely high so only a small number of people have the means to produce the chips. Economically it might not make sense to sell them and, to make the situation even worse, patents can prevent competitors being able to use the same innovations.
imtringued 7y ago
The first ASIC company can just keep the ASICs for themselves.

qaq 7y ago

Well aren't there BTC futures on CME?