This is a signed transaction. So the one who stole the prize.
One of the really interesting thing about the blockchain, is that you can write a smart contract script that will permiate forever.
using a hashed transaction instead of a signed transaction is a wierd mistake to make, but not an uncommon one of people who are just learning to write blockchain code. I know we are talking about BTC here and opcode is rather limited, but this type of thing pervades on ETH.
Imagine writing a PWN script as a 14 year old and waking up when you are in your late 20's to a millions dollars in crypto.
If the real puzzle solver didn't see this coming, he kinda does deserve it. Bitcoin blocks takes 10-20 minutes to confirm. This leaves enough time for a bot/human to take over. I am pretty sure he could have contacted a miner/pool and arranged a deal with them.
Ok there is one good explanation for this case that I found in another comment here [0]: the person who found the private key made a transaction moving only part of the full reward, but in doing so exposed the full public key. A was monitoring the puzzle address for activity, picked up the public key, used it to crack the private key quickly and moved the rest of the funds.
Fascinating that the original cracker wouldn't know these details about Bitcoin transactions.
You are right in the general case. But the public key is included in a transaction when it gets signed, and in this particular case the attackers already had part of the private key, that's what allowed a different attacker to combine both pieces and break the private key quickly.
I am not sure about this one but for the other puzzles, the solution is usually hashed and the submitter has to provide the solution in the Bitcoin script to solve for the hash. This disclose the solution (and thus the private key). This is not the case for signed Bitcoin transactions but these have special script functions. So if you don't use those, you lose these protections.
Can you explain that? So the real puzzle solver could have theoretically triggered the transaction, but lurking bots are stealing the transaction from them?
I'll try to give a brief here about how Bitcoin script works but you'd better read up on the Bitcoin wiki.
Essentially, to make a transaction valid, your script needs to pass.
1. <PubKey> + <Signature> -> This is how most transactions are handled. You provide the transaction with a signature. This doesn't expose your private key and lock the receiver. (as the receiver is signed)
2. <Hash> + <Hashed Content> -> To solve for Hash, you need to provide the Hash Content essentially solving the puzzle. Problem is, if you provide the Hashed Content publicly in the Script, anyone can also submit a competing transaction and set himself as the receiver.
the global warming consensus dominates the public discourse, the idea that somebody involved in crypto is not aware of energy consumption is a bit absurd
are we talking about people doing bitcoin mining or hash cracking?
bitcoin mining is an extremely competitive business of finding the cheapest sources of energy and mining hardware; because the cheapest energy sources are all renewable, mining bitcoin with fossil-fuel-produced power is unprofitable. so the electricity we're using to mine bitcoin is mostly solar, wind, and hydroelectric
as for the cracking, i don't think we know anything about where it was done or how much energy was needed, but if the energy cost was significant, i'd expect the solver to have done it somewhere where energy was cheap
electricity is basically fungible (minus a distance factor). So if you're using up the cheap, renewable electricity for mining, guess what you're using for everyone else's day-to-day electricity? Yep, fossil fuels. (https://www.theguardian.com/technology/2022/feb/18/bitcoin-m...)
One major exception to this is geothermal electricity in places like iceland where there's abundant green electricity, but you can't transport it to any neighbors.
So just using renewable sources for electricity doesn't actually make mining renewable until we're in a society that's 100% renewable.
the distance factor is a primary consideration when it comes to electricity; most electricity is consumed within hundreds of kilometers from where it's produced, because only in china is there uhvdc transmission, and even inside china there isn't nearly enough uhvdc and hvdc transmission capacity to meet demand
consequently, there are lots of places where there's abundant green electricity that can't be economically transported to any neighbors, which is why green electricity is cheaper than coal, nuclear, and gas energy. if it could be economically transported, it would be; instead, it is sold locally at much lower prices. only rarely is this seen by residential end-users, but in much of the world the 15-minute prices paid on the wholesale market by electric utilities are public information, so you can easily verify this
as a result of that, just using renewable sources for electricity does actually make mining renewable
as for the grauniad article, there are a lot of people doing unprofitable business things in lots of businesses, but they tend to be self-limiting, because those people run out of money before long
