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This is a great reminder that having an algorithm that can be secure doesn't mean it actually is. And it's kinda scary that coins that claim to have millions o

by pornel 5y ago

This is a great reminder that having an algorithm that can be secure doesn't mean it actually is. And it's kinda scary that coins that claim to have millions of dollars in market cap can be attacked for a price of a sandwich.

belter 5y ago
I wont touch anything that has the name Bitcoin, cryptocurrency, etc....With a 10 foot pole. Still, I like to keep up with events within the field. However its is stunning: Ethereum market cap $313.09 B ( yes with a B ), and you can pull off a 51% Attack for 1.5 million dollars ? Litecoin market cap $12.51 B and you can pull off a 51% Attack for 250 thousand dollars ? It seems Vitalik Buterin gives frequent interviews. Anybody aware if has been asked about this ? Can any of you with comment on the technical validity of this info. Because frankly, if this all it takes, I am tempted :-)
- amelius 5y ago
  Shouldn't the table also list the potential profit to be made from such an attack?
  - joking 5y ago
    very little, once you prove that an attack of those characteristics is feasible, the entire house of cards where the “value” of those coins is stored, would collapse, and you would gain nothing from it.
    - KebabLove 5y ago
      You are wrong. ETC got 51% attacked 3 times in a month, with no real effect on the price.
    - deleted 5y ago
      [deleted]
    - jpalomaki 5y ago
      Malicious actor might be able to make a profit by shorting related stocks and playing with cryptocurrency derivatives.
    - usrusr 5y ago
      Basically this. I think the more interesting question is how it might be possible to extract value from dominating log writes in more subtle ways. If stock market HFT can be a entire industry, what might be possible by tipping the scales of transaction latency?
  - nfin 5y ago
    good remark, as a 51% attack does does not let you do many things. An attack does not mean, that you can pull off anything. For example with most cryptocurrencies even with an 51% attack you can't change "from who", "to who" (destination) and also not the "sending amount". Requirement: - most (or enough) people do run a validating node (and not just a SPV wallet) => That is why Bitcoin proponents to insist so much on keeping the main blockchain small and therefore secure (other solutions like lightning, ... can then be level 2 built on the secure layer. But without secure layer 1, you have nothing secure to begin with / built less upon... like less decentralised but more scalable solutions)
    - wmf 5y ago
      You can change your own transactions which is usually the idea behind 51% attacks. You could deposit coins into an exchange then rewrite that transaction.
      - nfin 5y ago
        yes that’s why less secure (economicly game theoric wise) blockchains need longer confirmations (of course, it is also dependent of other factors like time to produce a block), as the probability of it happening with longer confirmation times decreases
- rattlesnakedave 5y ago
  it’s basically impossible to sustainably 51% Bitcoin or ETH at this point. You could 51% for an hour (maybe, if you can get that hash rate from nicehash for that long, but I doubt you actually can), but what happens at the end of that hour? Would everyone simply throw their hands up, allow your double spend, and keep mining your chain? Likely not. Andreas Antonopoulos has a good take on this for Bitcoin: https://youtu.be/ncPyMUfNyVM https://youtu.be/ncPyMUfNyVM
  - osigurdson 5y ago
    It is interesting that it is no longer an algorithmic consensus among machines but rather a consensus among humans. Could anyone comment on how such "reversal" type discussions take place and how many actors are involved? If power is sufficiently concentrated the fact that this can occur is a bit of a concern in itself.
- TheTester 5y ago
  ""How is the attack cost calculated? Using the prices NiceHash lists for different algorithms we are able to calculate how much it would cost to rent enough hashing power to match the current network hashing power for an hour. Nicehash does not have enough hashing power for most larger coins, so we also calculated what percentage of the needed hashing power is available from Nicehash. Note that the attack cost does not include the block rewards that the miner will receive for mining. In some cases this can be quite significant, and reduce the attack cost by up to 80%."
ClumsyPilot 5y ago
We've had 10 years of crypto economy, and yet, to this day, there has not been a single 51% attack on any major coin. In the same time preiod we have seen mutiple hacks again banks, governments and the military. The proof is in the pudding

by pornel 5y ago

belter 5y ago

I wont touch anything that has the name Bitcoin, cryptocurrency, etc....With a 10 foot pole. Still, I like to keep up with events within the field. However its is stunning: Ethereum market cap $313.09 B ( yes with a B ), and you can pull off a 51% Attack for 1.5 million dollars ? Litecoin market cap $12.51 B and you can pull off a 51% Attack for 250 thousand dollars ? It seems Vitalik Buterin gives frequent interviews. Anybody aware if has been asked about this ? Can any of you with comment on the technical validity of this info. Because frankly, if this all it takes, I am tempted :-)

amelius 5y ago
Shouldn't the table also list the potential profit to be made from such an attack?
- joking 5y ago
  very little, once you prove that an attack of those characteristics is feasible, the entire house of cards where the “value” of those coins is stored, would collapse, and you would gain nothing from it.
  - KebabLove 5y ago
    You are wrong. ETC got 51% attacked 3 times in a month, with no real effect on the price.
  - deleted 5y ago
    [deleted]
  - jpalomaki 5y ago
    Malicious actor might be able to make a profit by shorting related stocks and playing with cryptocurrency derivatives.
  - usrusr 5y ago
    Basically this. I think the more interesting question is how it might be possible to extract value from dominating log writes in more subtle ways. If stock market HFT can be a entire industry, what might be possible by tipping the scales of transaction latency?
- nfin 5y ago
  good remark, as a 51% attack does does not let you do many things. An attack does not mean, that you can pull off anything. For example with most cryptocurrencies even with an 51% attack you can't change "from who", "to who" (destination) and also not the "sending amount". Requirement: - most (or enough) people do run a validating node (and not just a SPV wallet) => That is why Bitcoin proponents to insist so much on keeping the main blockchain small and therefore secure (other solutions like lightning, ... can then be level 2 built on the secure layer. But without secure layer 1, you have nothing secure to begin with / built less upon... like less decentralised but more scalable solutions)
  - wmf 5y ago
    You can change your own transactions which is usually the idea behind 51% attacks. You could deposit coins into an exchange then rewrite that transaction.
    - nfin 5y ago
      yes that’s why less secure (economicly game theoric wise) blockchains need longer confirmations (of course, it is also dependent of other factors like time to produce a block), as the probability of it happening with longer confirmation times decreases
rattlesnakedave 5y ago
it’s basically impossible to sustainably 51% Bitcoin or ETH at this point. You could 51% for an hour (maybe, if you can get that hash rate from nicehash for that long, but I doubt you actually can), but what happens at the end of that hour? Would everyone simply throw their hands up, allow your double spend, and keep mining your chain? Likely not. Andreas Antonopoulos has a good take on this for Bitcoin: https://youtu.be/ncPyMUfNyVM https://youtu.be/ncPyMUfNyVM
- osigurdson 5y ago
  It is interesting that it is no longer an algorithmic consensus among machines but rather a consensus among humans. Could anyone comment on how such "reversal" type discussions take place and how many actors are involved? If power is sufficiently concentrated the fact that this can occur is a bit of a concern in itself.
TheTester 5y ago
""How is the attack cost calculated? Using the prices NiceHash lists for different algorithms we are able to calculate how much it would cost to rent enough hashing power to match the current network hashing power for an hour. Nicehash does not have enough hashing power for most larger coins, so we also calculated what percentage of the needed hashing power is available from Nicehash. Note that the attack cost does not include the block rewards that the miner will receive for mining. In some cases this can be quite significant, and reduce the attack cost by up to 80%."

ClumsyPilot 5y ago

We've had 10 years of crypto economy, and yet, to this day, there has not been a single 51% attack on any major coin. In the same time preiod we have seen mutiple hacks again banks, governments and the military. The proof is in the pudding