Bitcoin Forum

We don't know whether quantum computers will exist or not, but assume they will be built and some QC owners will move the early mined coins. What will happen?

Case 1
They (QC owners) could move the early mined coins, which are mined to P2PK addresses and haven't been moved since then.
They could let these coins there for a certain time to give potential owners the possibility to prove (signed message) that they are the owners and transfer these coins to them.
If there is no owner, the QC owners are the new owners.

Case 2
Some BTC owners will not accept case 1. They will create a hard / soft fork and burn these early mined coins.

In both cases we have to implement QC resistant addresses immediately.


Case 3
They (QC owners) will move all possible coins (also from active addresses).
In this case the Bitcoin price would collapse and it would end the Bitcoin project.



Case 1 gives the QC owners the possibility to improve our Bitcoin network and make it quantum resistant and reward them with these early mined coins. If there are still owners of early mined and not moved coins, they have the chance to move the coins and will get them back even after being moved, if they prove it (signed message) within a certain time period. Case 1 would lead to a smooth transition to a quantum resistant Bitcoin network and would be the strongest fork.

~~~ reserved ~~~

LONG BEFORE before any actual Quantum Algorithm AND Quantum Computer exists that would allow someone to access the bitcoins secured by P2PKH, Bitcoin will already have moved to a quantum-resistant authorization algorithm.  This will prevent Case 3, prevent the need for Case 2, and will allow plenty of time for any users that are still able to access their bitcoins to move those bitcoins with a quantum-resistant transaction.  The coins that are still remaining in the weak transaction outputs once Quantum Technology becomes a realistic threat will be those coins that are effectively "lost".  The QC owners will become the new owners of those coins, and Bitcoin will carry on as it always has.

You got it and support a strong Bitcoin network.

From what I know, quantum computers will appear only in 10 years. The "companies of evil" (IBM, Google etc) will not allow this happen sooner.

The real question lies on how long quantum computers would be fully-functional and operational in large scale and not just existing in laboratory conditions. Anyway, I'm pretty sure the community and the developers working on bitcoin know the possible threat of quantum computing should it ever go live within the tech space. Before that goes full-blown, we may have moved to a completely quantum-resistant algorithm that deflects any sort of brute-forcing and/or possible exploits affecting P2PKH addresses.

Should coins that were mined early and are deemed inaccessible were retrieved by QC owners and the community knew about it, perhaps a fork would be proposed and we'd take it from there and accept the fact that these coins are permanently lost in the void without any chance of retrieval.

The bitcoin community is comprised of bright minds capable of coming up with solutions even to theoretical problems, so I'm banking on that fact heavily.

Actually yes there is a known Quantum PC now.
Google claim they have an operational quantum pc: https://www.ft.com/content/b9bb4e54-dbc1-11e9-8f9b-77216ebe1f17


But you shouldn't fear from quantum computer. It is still hard to hack any crypto wallets. And also quantum computers can mine cryptocurrencies faster than ever.

The fact is everything evolves, if there is a technology that will attack certain protocols then it will evolve, if someone creates a Quantum Computer then they will plan to something that will benefit them rather than destroying something, that been said you need not worry about one in the next 20 years.

The time interval does not change :P and the price is not affordable to built a Quantum Computer to mine BTCitcoin and even if someone creates i doubt it will be able to overpower all the hashing power around the world and hence it is an impossible task. If someone is creating specifically to mine BTCitcoin then he must be really crazy and have a few millions at his disposal.

What do you mean in appear? To be quantum computers accessible for everyone? Maybe not in 10 but in 20-30 year that may happen and then quantum will be perceive as normal as current PCs. But on another hand google's quantum computer already exists.
OP every problem is solvable, what is computer? Combination of numbers and numbers are part of math. Math can create and solve problems, so when there will be that problem, it will be solved too and as DannyHamilton correctly mentioned quantum-resistant authorization algorithm.

Of course, we're talking about a possibility here. But a person's probability of owning a quantum PC for mining is always more likely than trying to hack a Bitcoin wallet. If I had a quantum PC, I'm sure I'd use it for much better things.

If Quantum Computers did exist (at great expense) - why would they waste that computing power on bitcoin which won't give them enough returns, compared to other uses they could put Quantum Computing to?

I don't understant why people are so convinced that QCs would be deployed in the cryptocurrency space which is only worth a few billion, compared to say stock markets or the trillion dollar forex markets where you could make so much more money?

 The description of how quantum computers work didn't capture why they are special; everything we always saying (e.g. superposition, computing everything in parallel) is also true of a "normal" computer equipped with random numbers. The thing that makes quantum computers special is the interference; some of the parallel paths can cancel each other out. Without that, superposition would be useless.

Also, it's not really true that the motivation for quantum computers is the physical limits of transistors. We started studying quantum computing long before those limits were a problem, and there's not much overlap between people working on quantum computing and people working on smaller transistors. They're just separate issues - both interesting and important.

Do you think it's easy to own a quantum computer? I am sure NO, the value of a quantum computer is extremely large, do you think someone uses its power just to mine bitcoin? I'm sure no one does that stupid thing, quantum computers should be used for more complex and important calculations.

According to some previous news, the first quantum computer was created by Google, it is no longer a distant thing.

We will have a quantum resistant Bitcoin network, there is no doubt. But we will have two main Bitcoin forks post quantum.

The question is which of the two main Bitcoin forks will be supported.

1. A Bitcoin blockchain with all existing coins (also Satoshi's early mined coins and other early mined coins with no owner). Here the QC owners will remove those coins and will be the new owners and the community 1 of this fork will accept it as a reward to QC owners. If there were owners of early mined and not moved coins, they could have moved these coins. As they didn't, the community 1 will handle them as "lost" coins.

2. A Bitcoin blockchain without the early mined coins. Community 2 will not accept it that someone (QC owners) gets the early mined coins and will burn them.

When objects of value are found in a ship wreck at the bottom of the sea, should those that managed to find the wreck be allowed to profit from that find?  Or should a government agency take evderything salvaged and destroy it?

Some BTC owners think that if you burn the early mined coins and don't give the QC owners the possibility to get these, then the supply will go down and their coins will be more valuable. But you never know which coins will be burned next.

And some support the "21 million BTC supply" and let the QC owners get these coins. In that case we are responsible for our coins and if coins aren't being moved from old accounts to newer ones, we assume that these coins are "lost" and if QC owners develop a computer to get them, so it's their reward. But these group will always know that their coins won't be burned. Never. And therefore this blockchain will be the strongest.

It is a different thing, if someone hacks your computer and gets your coins or if a QC owner gets the "lost" coins.

"long before" implies you know when QC will be capable of breaking ECDSA. when will that be---and accordingly, when will bitcoin developers discuss which quantum resistant scheme to implement, and when to implement it?

what constitutes "plenty of time" for users to upgrade? considering how slowly users adopted P2SH or segwit outputs, bitcoin should probably implement quantum resistant signatures many years before the threat is even remotely real. otherwise many millions of coins could be stolen, just by virtue of today's common practices of address reuse, xpub sharing, etc.

upgrading to a post-quantum protocol in a conscientious way will take several years at least. when are we gonna start discussing the details?

When cryptographic community as a whole will reach both 1) a consensus on what quantum-ready algorithms will become the standard and 2) decide that it's time to start switching to it.
There's no need for Bitcoin to be on the cutting edge cryptography, it would only mean unnecessary risks and forks after forks.

quantum resistance =/= cutting edge. lamport signatures are from the 70s. :P

centralized entities can quickly implement new encryption and reverse most of the damage done if QC breaks current standards. they can afford to wait. bitcoin is irreversible, and people take years to upgrade. there would be 5 million+ coins up for grabs if QC broke ECDSA today---and that's not even considering p2pkh inputs that might be stolen in-flight.

if we want to reduce that number (ie prevent many millions of coins from being stolen) we need to act sooner than later, because again---people take years to upgrade their bitcoin software. by various estimates, ECDSA could be broken within 3-7 years. (https://medium.com/@nopara73/stealing-satoshis-bitcoins-cc4d57919a2b) that doesn't leave us much time.

People don't upgrade their nodes because they are compatible with the network, if there was a hardfork, you can expect them to switch rather quickly. Look at ETH or other alts, they have hard forks almost every year and they go pretty smooth.

If quantum computers became real today, the world would be in a lot of trouble - bank account, emails, websites, military communications, classified data and so on - but you don't see them proactively moving to post-quantum crypto right now, which means that the cryptographic community doesn't view as an immediate threat. And cryptographers usually retire algorithms long before they become not even fully broken, but just weakened.

a hard fork is not required to implement a post-quantum signature scheme. (that's probably a good thing since bitcoin isn't some centralized shitcoin---BCH and BTG are what happens when people try to hard fork it)

what are you saying---that we can literally just wait until ECDSA is broken and then do an emergency hard fork? that won't work. by then it's too late: QC could possibly break transactions in-flight, meaning the entire bitcoin supply is at risk of theft---outputs being moved to quantum safe addresses could be stolen in that scenario. even if QC weren't fast enough to do that, there would be 5+ million coins ready for the taking on day 0. (https://twitter.com/pwuille/status/1133532495784267776) are you considering the potential consequences of that?


centralized organizations can implement new encryption standards at the drop of a dime. bitcoin cannot do that because it's decentralized. and as outlined above, its inability to do so puts the entire monetary base at risk.


some cryptographers say ECC/ECDSA will be broken in the next several years......

I don't think that today's quantum computers are capable of doing much harm as they are very limited in the tasks that they are able to perform.  As of now quantum computers can only serve as and solve a limited or  specific amount of functions.The tech is at ts infancy and will take time to progress some. I think that people have a preconceived notion pertaining quantum computers that derives from science fiction fandom, whose media isn't too far from the truth.

Yes, this technology is still in its infancy, but at the current rate of technological development in the world, in a short time, it will develop with full functionality. However, what I disagree with is using in other declarations. I think no madman is using a precious quantum computer just to mine bitcoin. It certainly won't be mass-produced, of course not for ordinary mines to buy, and its price is even quite expensive.

Technology is rapidly evolving in our age, and it won't take too long before this Quantum Computers will take over the blockchain and destroys it, that is why we are hoping they won't get that far because we are doomed once that happens, and when that time comes, I bet you would take back these words that you have said, and rephrase it to something more wary about quantum computers in the future. :)

In the near future QC owners will be only really big firms and them dont want to mine shitcoins sorry

Hate to burst your bubble my friend but Quantum Computers aren't even existing yet. There is a huge possibility of it coming in the future but with the current technology we have right now it is too unlikely, so you won't need to worry about bitcoin's status just yet soon as quantum computers come around.

If you buy these BitCoins, the 24 Karat ones that cost around 1550 per ounce, you will not have to worry about a quantum computer taking them away from you  ;D ;D ;D

https://i.imgur.com/u6MUK2l.jpg

Hard Facts

The hype around quantum computer isn't that great.  It was exaggerated by writers who wanted to have huge amount of views.  Besides, this FUD that spreads  like what OP stated will not happen because Bitcoin developers are already looking for solution before the implementation of quantum computers.  In short, Bitcoin  will be QC resistant before what we fear happens.

If nothing is done they would sell them, price would go down a bit, people would buy the cheap coin, price would go back to normal. See? the market self regulates as usual. You know it is the exact same scenario if Satoshi returns to do the very same?

You people always fail to realize that selling large amount of Bitcoin does NOT happen instantly, and the fact that it takes several operations changes things considerably to what some people theorize.

And like you say, some might just keep them, because why not? I guess its some sort of unofficial prize for successfully building such computer.

You say "some" won't accept it? That won't do. A hard fork takes a considerably amount of consensus. I doubt this will be the case, to imply it would be the same mistake made by Ethereum, and Bitcoin has long proven they are not.

You cannot collapse the price of bitcoin (permanently as you imply, anyways). No matter how many Bitcoin you attempt to sell, the market will buy them probably faster than you are able to sell them anyway. This is what you fail to see, operations are not instant. Whales don't have as much manipulating power as you think, not even Satoshi.

You have no case.

1. there's no functioning quantum computer. Prototypes don't count.
2. it's still incredibly hard to translate current computer files into a language understood by a quantum computer and back
3. it will take decades until private contractors are able to buy their own quantum computers and their price is going to be very high if that happens

The above points make the question invalid. Let's wait until there's at least one functioning computer able to perform a task of breaking any SHA 256. I bet the first things they do with it won't be breaking into the genesis block. There are satellite codes, encrypted CIA files, nuclear missile codes...

Whoever makes a quantum computer work will never have to worry about money so he won't have to try to damage his reputation stealing  from Satoshi.

I agree  that quantum computers can't do any harn to cryptocurrencies, there is no reason to fear. Maybe in the future if they significantly improve their capabilities although they will develope further, that is for sure. Also, they are not in mass use and individuals are not buying them yet and will not for a longer time.

If quantum technology is ever put to use i'd be more afraid of your fiat money.

If encryption can be broken so are the bank vaults holding your money on the servers. Nowadays money making is not only done with printers. They add a few zeroes to your bank account and you're set. Nobody will know about it until it's too late.

Stop spreading FUD about quantum computers.

I'd go further and say that your points make the OP simply just FUD.

I guess I am growing weary of seeing this non issue keep getting posted.  Get over it, a real general processor based on "quantum" computing tech is so far off that its ridiculous to even mention it in terms of threatening bitcoin in our lifetime.

I could have easily posted an equivalent titled thread "Will the future human colonies on Mars and Titan threaten bitcoin ?", and it would be about as meaningless as all of the "quantum computer threaten btc" threads.

Everyone should start to recognize these threads for what they are, just FUD.

All people who say that quantum computers won't exist: who will give them back their Bitcoins if they don't improve the network and don't transfer to quantum computer resistant addresses?

Quantum computers will exist.


We will have a quantum resistant upgrade. People will transfer their coins to quantum resistant addresses, but a lot of coins (million+) won't be moved to these secure addresses as they are "lost" coins and nobody can move them.
Which fork will you use post quantum?
a) the fork with all Bitcoins where quantum computer owners will get the "lost" coins and will be the new owners.
b) the fork where "lost" coins are burnt and can't have new owners.

https://www.digicert.com/resources/industry-report/2019-Post-Quantum-Crypto-Survey.pdf
Slightly more than half (55 percent) say quantum computing is a “somewhat” to “extremely” large threat today,
with 71 percent saying it will be a “somewhat” to “extremely” large threat in the future.

I read through your linked pdf...

According to what you've posted, that's 55 percent and 71 percent of Enterprise IT.

It is NOT 55 percent or 71 percent of "experts", or "knowledgable individuals", or "educated individuals".

Furthermore, according to what you've posted...

"59 percent, of those SAME "Enterprise IT" individuals, claim to currently be deploying hybrid (PQC + RSA/ECC)
certificates"

This is:
"something that is unlikely as PQC certificates availability is limited to early testing
situations"


Furthermore:
"71% say they are 'somewhat' to 'completely' aware of PQC, but that’s not the entire story. We followed up with a question designed to test if they truly understood what PQC means. Less than two-thirds knew the correct definition."

Clearly, your reported "55 percent" and "71 percent" aren't exactly what I'd call "reliable sources".  Their opinions about the threat of quantum computing aren't very compelling.

It is very interesting. If a quantum-robust authorization algorithm protects bitcoin, will altcoins be able to protect themselves from the capabilities of quantum computers? If bitcoin remains invulnerable to them, then it is possible that the advent of quantum computers will even be useful for bitcoins in the sense that it will be possible to return to circulation over six million bitcoins that are now irretrievably lost.
However, I still fear the advent of quantum computers. This will provide additional opportunities for all kinds of hackers and scammers.

You're talking about some kind of cyberpunk. It seems to me no one will dare to destroy the Bitcoin project, just think about what consequences it will end.

1+ million Bitcoins, the other "lost" coins are QC resistant



We want to make Bitcoin better and stronger.



We don't think that QC development will happen step by step. Our expectation is that someone will find a QC technology, that allows "far beyond expectations" numbers of qubits, that will allow this QC to get all private keys immediately.
We think that such a QC will surprise the Bitcoin community and only thereafter we will upgrade to a quantum resistant Bitcoin network. We hope that the user of such a QC to get the private keys, knows exactly how Bitcoin works and allows the owners to transfer their coins to the new QC resistant addresses. It would be a win-win game: the QC user would get the "lost" coins, the Bitcoin owners could transfer their coins to QC resistant addresses, the Bitcoin ecosystem wouldn't be affected, we would have a stronger Bitcoin network. How would a QC user act: starting with the oldest "lost" coins and moving them, so that the Bitcoin community can realize that someone is moving the "lost" coins (e.g. a special posting board here on bitcointalk) but gives the owners the possibility to transfer their coins to other addresses. In the meantime we will have a very quick "quantum resistance upgrade". And it will continue like DannyHamilton described it:
but stronger

I'll admit my understanding of how Bitcoin works certainly isn't the deepest, but why specifically are P2PK addresses mentioned?  Are not P2SH and Bech32 addresses vulnerable to the theoretical QC threat?

The other "lost" coins are "first generation quantum computers" resistant. "Second generation quantum computers" that include hashing algorithms will get them.