Bitcoin mining hash rate drops as blackouts instituted in China

Post by Thorrez » Sun, Apr 18, 2021, 6:15 AM UTC

sillysaurusx wrote: post #74

yuvadam wrote: post #67

Earlier quoted context omitted.

"Rolling back" the network means successfully creating a new longest chain that forks off of an arbitrary old block. The further back in time you to "rollback" to, the less probable it is for the 51% to successfully mine all those needed blocks to get up to par with the existing longest chain. Realistically speaking, this sort of attack is highly improbable.

Indeed. See the "bitcoin snack machine" for some hard numbers: https://bitcointalk.org/index.php?topic=423.0 > The network nodes only accept the first version of a transaction they receive to incorporate into the block they're trying to generate. When you broadcast a transaction, if someone else broadcasts a double-spend at the same time, it's a race to propagate to the most nodes first. If one has a slight head star…

Post by foepys » Sun, Apr 18, 2021, 6:19 AM UTC

arcticbull wrote: post #64

foepys wrote: post #39

Earlier quoted context omitted.

And in the event of an attack you just hope they won't target nuclear power plants to recreate Chernobyl and Fukushima?

Nuclear reactors are very much hardened against such attacks, and of course, those were both very different situations. No need to spread FUD about the safest form of electricity in the entire world in terms of deaths per TWh. [1] It's also roughly zero carbon. You know the worst nuclear accident, Chernobyl, killed 4000 people in the full course of time - and we've learned a ton since then. Fukushima killed 1 person.…

Post by oefrha » Sun, Apr 18, 2021, 6:19 AM UTC

mr_woozy wrote: post #79

oefrha wrote: post #72

A good reminder that Bitcoin runs on cheap renewables is BS. See also miners buying gas power plants in New York.[1] [1] https://news.ycombinator.com/item?id=26828479

sure if you're suddenly not counting China's hydropower as renewables suddenly.

Post by RobLach » Sun, Apr 18, 2021, 6:22 AM UTC

jabbany wrote: post #66

2bitencryption wrote: post #14

> Significantly, the Xinjiang and Sichuan regions of China combined account for more than 50 percent of the overall Bitcoin mining hash rate I don't get it, doesn't this effectively mean China can force a 51% attack by just strongarming the pools that operate there?

In theory yes, but in practice it's rather infeasible to do 51% attacks IRL --- the main constraint is the people not the math. A 51% attack mainly lets you double spend, so you have to: (1) get a lot of coins and spend them on something (2) start mining a fork where that spending didn't happen (but other real transactions continue to happen) --- your hash power will now need to be dedicated to this new fork at the e…

Post by [deleted] » Sun, Apr 18, 2021, 6:24 AM UTC

dangero wrote: post #59

c54 wrote: post #54

Earlier quoted context omitted.

> doesn't this effectively mean China can force a 51% attack by just strongarming the pools that operate there? Yes, in theory. There's a coordination problem to get all the pools to do what you want, but if they (or anyone) could pull that off, then yes. So then what happens? If a single entity controls >50% of the hash power of the network, they could start finding blocks with arbitrary (invalid) transactions and a…

inserting invalid transactions is not the double spend issue. If their hash rate is over 50% they can "unconfirm" a confirmed transaction by making a chain with more work on it. This is how the attack plays out in simplified form: Bitcoin is sent to an exchange by the attacker, confirmed, sold and withdrawn for cash. Attacker then makes a chain with more work on it than the chain where the Bitcoin was sent to the exc…