Quote from: ranochigo on Today at 05:08:18 AM

Quote from: PrimeNumber7 on Today at 03:17:26 AM

I have made similar arguments in the past, and I stand behind those arguments. I don't think this means QC can be ignored though. Once the West and the Communists in the East (most likely the US and Chinese respectively) have QC tech, knows the other side knows they have QC tech, and knows that the other side knows they have QC tech, the incentive to keep the technology under wraps goes away.

If QC technology is used to crack bitcoin private keys, it will probably be too late to move away from EDSCA and confidence in bitcoin security will be lost/damaged. Using QC technology to crack bitcoin private keys will also cause a lot of damage throughout the bitcoin economy, and it has the potential to cause a lot of businesses to go out of business.

The threats of quantum computers are very real. That does not discount the fact that the incentives to attack Bitcoin pales in comparison to the other things that you can do with QC. You're assuming that we won't be able to at least adopt another QC resistant standards before it becomes a threat. Long before Bitcoin becomes a target, I would assume that we would've adopted another QC resistant algorithm. QC technologies seems to have an incremental improvement over the years and I don't think that a 2000qubit QC machine would be discovered overnight. As a state, I would think that they are more interested in collecting encrypted information rather than cracking a few Bitcoin keys, and I think the estimates for a ~1500qubit machine puts it at one PK per hour. I'm not exactly sure of the running costs of a quantum computer but I would probably think that it's not worth their time at an early stage where you would probably need a very precisely controlled conditions to keep it stable.

Bitcoin prices will probably crash if that type of QC gets discovered overnight, so will the stocks market. QCs are after all not the primary threat to Bitcoin, but to all existing internet infrastructure.

Yes, Bitcoin will definitely be affected by QC but the fact that it *probably* cannot be mass produced in the first place will bring about some doubts if people would want to start cracking the keys if they (the states) could stand to gain much more by starting to decrypt previously intercepted internet traffic. Anyhow, I would regard all of the discussions as speculations. If quantum computers gets cheap enough and collecting money is their main goal, then attacking a currency like Bitcoin could make some sense though the effects will be limited.

QC can be used to decrypt encrypted communications between governments and their spies. It can also be used to decrypt encrypted military communications, and potentially impersonate the military command to military weapons. The above are likely the first use cases for QC technology that governments have access to and can keep secret.

If a government is researching QC technology, they are not necessarily going to make their progress public, nor will they keep the public informed about the status of the QC technology they have developed in any way. This means you will not know how effective the state of the art QC computers are.

In some amount of time, the US government is going to have access to QC technology that can trivially crack PK from a public key. The same is true for the Chinese government. At this time, neither will want to use the technology to steal bitcoin because they can use the technology to decrypt sensitive communications the other is sending. Once the US knows the Chinese have this technology (and vice versa), the technology is no longer useful for espionage because both governments will transition to QC resistant means of encryption.

There is also the risk of a rogue employee that could use QC technology they have access to in order to steal coin. Each of satoshi's mined blocks is currently worth about $1.75 million, which is a lot of money for anyone.