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> - nobody owns Bitcoin network => delivered; For a state actor it would actually be quite trivial to mount a >50% attack. If you own >50% of the hashrate, you

> - nobody owns Bitcoin network => delivered; For a state actor it would actually be quite trivial to mount a >50% attack. If you own >50% of the hashrate, you own the network.

pharmakom 4y ago
I doubt it would work in practice. If an actor repeatedly used ASICs to run a 51% attack, it wouldn’t take long for the community to switch hashing algorithm and render all that hardware useless.
- pishpash 4y ago
  How is "the community" going to switch when "the community" includes the 51%?
  - pharmakom 4y ago
    Everyone in the community who isn’t the 51% attacker would want to switch because a crypto that is vulnerable in this way has little value.
2Gkashmiri 4y ago
if someone "mounts" a 50% attack and is successful, do you think the rest of the world will simply accept their "attack"? bitcoin was forked into bitcoin cash once, why cant it happen again?
- sgjohnson 4y ago
  The bitcoin cash fork is incomparable, because it wasn't done because Bitcoin itself was under attack. It doesn't even matter if there'd be a fork. It would be a significant disruption at the very least.
- pishpash 4y ago
  By what mechanism would they not accept? Sure you can leave and create a new network, as much as you can choose one of the many other cryptos already out there.
qabqabaca 4y ago
While it may be trivial in implementation, its unrealistic due to the cost. >In reality, the Bitcoin network has proven resilient enough to withstand a 51% attack over the years. In fact, due to the size of the Bitcoin network and the extent to which hash power is decentralized, along with the cost of mining equipment, it’s prohibitively expensive to attack Bitcoin. We estimate it would cost over $13 billion https://learn.eqonex.com/news/what-51-attack-and-how-much-would-it-cost https://learn.eqonex.com/news/what-51-attack-and-how-much-wo...
- sgjohnson 4y ago
  > We estimate it would cost over $13 billion So basically it's less than what the U.S. Federal Government spends in one day (FY2021 spending totalled $6.83tn). Unrealistic.
  - tenuousemphasis 4y ago
    That's $13 billion for the hardware, and $1 million per day in electricity assuming a cost of $0.01/kWh
    - Sparyjerry 4y ago
      $13 billion is a drop in the bucket for governments. The have been passing Trillion dollar bills for some time.
tenuousemphasis 4y ago
You have to continue executing the 51% attack forever, or else when you stop, the network goes back to normal. And about the worst thing you can do during such an attack is prevent transactions from confirming. You can't unilaterally rewrite the ledger, you can't steal money from people. So saying you "own the network" while executing such an attack is... pretty dumb.
- sgjohnson 4y ago
  > And about the worst thing you can do during such an attack is prevent transactions from confirming. You can also double, triple or quadripule spend bitcoins and have those transactions confirm. Yes, they’ll get marked as double spends, along with everything down that chain, but that’ll only happen once the network goes back to normal, and it would absolutely wreak havoc. So no, it’s not just “all you can do is a denial of service”.

> - nobody owns Bitcoin network => delivered; For a state actor it would actually be quite trivial to mount a >50% attack. If you own >50% of the hashrate, you own the network.

pharmakom 4y ago

I doubt it would work in practice. If an actor repeatedly used ASICs to run a 51% attack, it wouldn’t take long for the community to switch hashing algorithm and render all that hardware useless.

pishpash 4y ago
How is "the community" going to switch when "the community" includes the 51%?
- pharmakom 4y ago
  Everyone in the community who isn’t the 51% attacker would want to switch because a crypto that is vulnerable in this way has little value.

2Gkashmiri 4y ago

if someone "mounts" a 50% attack and is successful, do you think the rest of the world will simply accept their "attack"? bitcoin was forked into bitcoin cash once, why cant it happen again?

sgjohnson 4y ago
The bitcoin cash fork is incomparable, because it wasn't done because Bitcoin itself was under attack. It doesn't even matter if there'd be a fork. It would be a significant disruption at the very least.
pishpash 4y ago
By what mechanism would they not accept? Sure you can leave and create a new network, as much as you can choose one of the many other cryptos already out there.

qabqabaca 4y ago

While it may be trivial in implementation, its unrealistic due to the cost. >In reality, the Bitcoin network has proven resilient enough to withstand a 51% attack over the years. In fact, due to the size of the Bitcoin network and the extent to which hash power is decentralized, along with the cost of mining equipment, it’s prohibitively expensive to attack Bitcoin. We estimate it would cost over $13 billion https://learn.eqonex.com/news/what-51-attack-and-how-much-would-it-cost https://learn.eqonex.com/news/what-51-attack-and-how-much-wo...

sgjohnson 4y ago
> We estimate it would cost over $13 billion So basically it's less than what the U.S. Federal Government spends in one day (FY2021 spending totalled $6.83tn). Unrealistic.
- tenuousemphasis 4y ago
  That's $13 billion for the hardware, and $1 million per day in electricity assuming a cost of $0.01/kWh
  - Sparyjerry 4y ago
    $13 billion is a drop in the bucket for governments. The have been passing Trillion dollar bills for some time.

tenuousemphasis 4y ago

You have to continue executing the 51% attack forever, or else when you stop, the network goes back to normal. And about the worst thing you can do during such an attack is prevent transactions from confirming. You can't unilaterally rewrite the ledger, you can't steal money from people. So saying you "own the network" while executing such an attack is... pretty dumb.

sgjohnson 4y ago
> And about the worst thing you can do during such an attack is prevent transactions from confirming. You can also double, triple or quadripule spend bitcoins and have those transactions confirm. Yes, they’ll get marked as double spends, along with everything down that chain, but that’ll only happen once the network goes back to normal, and it would absolutely wreak havoc. So no, it’s not just “all you can do is a denial of service”.