no you are reading that in a wrong way, i said that a 128 key for a quantum is like a 64 for a standard pc, in the sense that a standard pc can break 64 and a QC can break 128
well my intention was not say that it could break sha256, but all i want to said, is that it could break 128 key, that's it, there is nothing flawed about my logic
Your writing is bad. That's the issue. I told you, instead of posting a lot of uninformative posts, time would be better spent learning the language itself.
There is no logic and everything is flawed.
I've told you this already. There is no working quantum computer that can even begin trying to break that key. You should focus on reading rather that replying.
Yes, you would have a possible race condition and how well you are connection to the network would be very important. The attack you are talking about here assumes that Eve (attacker) gets the pubkey from Alice (user) before Bob (miner) confirms the transaction. Not only getting the public key, but also calculating the private key from it and creating a competing TX. Thus Eve would have to be in control of all peers Alice is connected to and all nodes Bob is connected to in order to make this a very likely success. If only a single node (of those connected to Alice) is not under Eves control the TX Alice creates will most likely reach Bob before Eve's.
This is a big problem, but it does not mean bitcoin is broken. It makes every single transaction risky until the problem is fixed though.
Depending on the costs to run a QC, this does not seems cost efficient even when possible. Once the first QC's are capable and start messing with TX I suspect[1] someone has a hardfork solution in some drawer.
[1] actually I have no idea how realistic this is, but considering that we have at least a decade Im positive.
Like I previously said quantum computers can't even begin to tackle the problem and that the user was pulling nonsense. Now he's just copying information from other people's statements.
