How will Quantum computing affect Bitcoin?

[ConnerDalfino]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

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[Lorence.xD]

We don't know the current peak capability of quantum computing as it is still in its early stages but one thing is sure that it will be a problem for bitcoin because as what is on the paper says about quantum computing, it will be far faster than any computer in the market and in any laboratories. We also have to stop telling people that quantum computing will be able to hack the private key of everyone, yes it has faster calculations but that doesn't mean that it will crack the key in a matter of days, if right now the current brute force duration is the heat death of the universe, maybe with quantum computing, the time it takes will be cut in half but that is still a whole lot of millennia.

[zanezane]

We don't know the current peak capability of quantum computing as it is still in its early stages but one thing is sure that it will be a problem for bitcoin because as what is on the paper says about quantum computing, it will be far faster than any computer in the market and in any laboratories.

You might be right but I am a firm believer that it can affect bitcoin big time, we can't see the peak but we can still imagine what it will do, remember the first computer which is the size of one room, they were much slower back then but we came to the stage that almost every household has a computer which means that quantum computer capabilities might do what we didn't expect it to do at unexpected speed.

We also have to stop telling people that quantum computing will be able to hack the private key of everyone, yes it has faster calculations but that doesn't mean that it will crack the key in a matter of days, if right now the current brute force duration is the heat death of the universe, maybe with quantum computing, the time it takes will be cut in half but that is still a whole lot of millennia.

I find it funny that people are talking about quantum computers breaking the security of blockchain so I wouldn't want them people to stop telling about it because I want them to see what they are going to say when you ask them why. Is that really the time it takes to crack the private key with brute force? That is a really long time, I might do some quick search about the duration but I am sure that it will not be as long as the death of universe.

[avikz]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

Quantum computers are a reality and not a myth anymore! Companies like IBM, Google have invested billions in their quantum computing project and has seen a preliminary success. It's definitely a threat to cryptography but not an immediate one!

Quantum computers are exceptionally costly to build and only a couple of nations have shown interest in it! If you think hackers will use such computers to launch an attack on cryptocurrencies like bitcoin, then you are daydreaming. Quantum computing is not yet a threat to cryptography, at least not now and not in immediate future!

[NeuroticFish]

Quantum computers are exceptionally costly to build and only a couple of nations have shown interest in it! If you think hackers will use such computers to launch an attack on cryptocurrencies like bitcoin, then you are daydreaming. Quantum computing is not yet a threat to cryptography, at least not now and not in immediate future!

Actually they've started to also build 5000$ quantum computers too. Of course, they are very weak (2 qbit) hence they don't need liquid helium for cooling.

And I think that you are also wrong about government financed quantum computers. In the same way super computers were used for crypto mining by this or that scientist with access to them, I can also expect this kind of "accidents" happen now and then with quantum computers too in the future.

But from what I've read (since there are plenty of threads here on this topic!) Bitcoin is pretty much safe from quantum computing and the only weakness (albeit theoretical) may be in the address reuse. (If I understood right). However, there are a lot of things in this world protected by cryptography, same or weaker than Bitcoin's, if this is hacked the problems will be .. generalized.

[aoluain]

By using the search facility the answers to this query can be found in approximately 4 seconds.

Its one of the most popular topics here on the forum, I got bored of copying links so I stopped at around 20.

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[ranochigo]

But from what I've read (since there are plenty of threads here on this topic!) Bitcoin is pretty much safe from quantum computing and the only weakness (albeit theoretical) may be in the address reuse. (If I understood right). However, there are a lot of things in this world protected by cryptography, same or weaker than Bitcoin's, if this is hacked the problems will be .. generalized.

As well as transactions that were in P2PK, which means most of the coins mined in the early days are vulnerable. It is not difficult to solve this issue for the transactions in the future but those with exposed public keys will inevitably be vulnerable still.

Important note: Most of the encryptions that you're using nowadays will be broken in tandem. Whether Bitcoin is a suitable target, it's too early to tell.

[20kevin20]

One particular way I'm afraid this could affect cryptocurrency is when privacy features come in. For example, if Bitcoin gets MW and QCs will be used against BTC, can't it basically be used to generate all possible seeds and not only link current addresses to each other (since coin control is no privacy enhancer anymore as soon as they have your seed) but also see where the money has come from (or been sent to)?

My fear is that they are using very advanced technologies before we even hear about them, hence being able to control the network (only in a surveillance, view-only mode!) in a way we previously thought was not very likely.

But as others said, if BTC is under attack through QC then there are so many other corporations, banks, governments etc that would be under a very serious threat as well. I think we can only suppose stuff about the damage QC can do until it becomes a consumer-end product. But by then, all the potentual threats are probably going to be erradicated..

[ranochigo]

One particular way I'm afraid this could affect cryptocurrency is when privacy features come in. For example, if Bitcoin gets MW and QCs will be used against BTC, can't it basically be used to generate all possible seeds and not only link current addresses to each other (since coin control is no privacy enhancer anymore as soon as they have your seed) but also see where the money has come from (or been sent to)?

I actually haven't thought of this at all and I was more fixated on how it would just exploit public key cryptography. I don't think QCs will be able to speed up the generation of seeds (or addresses), that significantly. After all, address generation involves both SHA256 as well as RIPEMD-160 while HMAC-SHA512 is used for BIP32 seeds to master private keys. While they should provide a speedup through Grover's algorithm, I doubt it would be fast enough to exhaust the key space. But of course, the xpub will be vulnerable to quantum computers the same way as how exposed public keys are.

[DapanasFruit]

I am not really so afraid of quantum computing to be affecting the integrity and security of Bitcoin. Anyway, in case it can really be possible for this technology to destroy Bitcoin then let it be. However, it can be taking years before we can see a full-pledged quantum computing to be perfectly working and by that time I am sure that Bitcoin has already got the necessary technological advances to counteract that possible threat. One thing for sure, we are all weak in predicting the exact future. 

[20kevin20]

I actually haven't thought of this at all and I was more fixated on how it would just exploit public key cryptography. I don't think QCs will be able to speed up the generation of seeds (or addresses), that significantly. After all, address generation involves both SHA256 as well as RIPEMD-160 while HMAC-SHA512 is used for BIP32 seeds to master private keys. While they should provide a speedup through Grover's algorithm, I doubt it would be fast enough to exhaust the key space. But of course, the xpub will be vulnerable to quantum computers the same way as how exposed public keys are.

Are QCs the fastest tech they have right now tho? I really think there's even better tech laying around in some underground base they're experimenting with. By the time usual customers will get to own a QC, they will already be many steps ahead with the technology. I don't think they would ever let QCs be a thing until they will already have something better ready under the glove.

If cryptography is compromised, then I think it's safe to say the entire network potentially is as well. I'm no expert though so feel free to prove me wrong. But then again, there will be ways to fight against this. Like any other type of tech, there will be ways to counter its attacks.

[ranochigo]

Are QCs the fastest tech they have right now tho? I really think there's even better tech laying around in some underground base they're experimenting with. By the time usual customers will get to own a QC, they will already be many steps ahead with the technology. I don't think they would ever let QCs be a thing until they will already have something better ready under the glove.

Well, you wouldn't ever know until it happens. It's safe to assume QC is the biggest threat to cryptography, anything else would be a speculation at this point. QCs, together with Shor algorithm will probably be the one that can feasibly factorize large integers.

If cryptography is compromised, then I think it's safe to say the entire network potentially is as well. I'm no expert though so feel free to prove me wrong. But then again, there will be ways to fight against this. Like any other type of tech, there will be ways to counter its attacks.

It is. Until we figure out a way to secure the millions of Bitcoins that are associated with the exposed public keys. I'll leave the feasibility and its cost aside, it isn't the main point of the topic.

[Argoo]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

Quantum computers are a reality and not a myth anymore! Companies like IBM, Google have invested billions in their quantum computing project and has seen a preliminary success. It's definitely a threat to cryptography but not an immediate one!

Quantum computers are exceptionally costly to build and only a couple of nations have shown interest in it! If you think hackers will use such computers to launch an attack on cryptocurrencies like bitcoin, then you are daydreaming. Quantum computing is not yet a threat to cryptography, at least not now and not in immediate future!

More recently, many on this forum assured that quantum computers can be created in at least ten years, so you should not be afraid of their computing capabilities. However, I recently read that low-power quantum computers are already being shipped to schools in China to learn how they work. That is, such computers have already been created and they are already working. But so far, little is known about their ability to crack digital codes. If this were possible, then many would already have raised the issue of hacking their wallets. I think that soon we will find out the answers to these questions.

[posi]

According to what I read quantum computer is a supercomputer that was said to be a serious challenge to blockchain security but I think will be 20years before we can see a quantum computer that will break blockchain security and before that time there's already a perfect solution to secure the blockchain network from a quantum computer.
I read that the non-regulatory agency of the United States Department of Commerce (NIST) has already started gathering proposals for post-quantum cryptography, encryption that would operate and not be broken even with much larger quantum computers than the ones we’re currently able to build so people shouldn't fear the capacity of the quantum computer.

[pawanjain]

By using the search facility the answers to this query can be found in approximately 4 seconds.

Its one of the most popular topics here on the forum, I got bored of copying links so I stopped at around 20.
~Snip

Bang on ! I was waiting for someone to post this and you did it in a better way.
I wonder why people don't use the search function when it can easily answer all our queries most of the time.
Procrastination ??

[suzanne5223]

Although, I am yet to understand the supremacy of the quantum computer but there's a chance the news and what was said about the quantum computer to break the blockchain is just a FUD to create some panic because SHA-256 which was used for Bitcoin is speculated to be quantum-resistant and the last time I checked Bitcoin client use SHA-512 (which is even stronger than SHA-256). If SHA-256 is quantum-resistant how will quantum pose a threat to SHA-512?
If SHA-256 and SHA-512 can be creak by a quantum computer in the future a soft fork is enough to make crypto safe from a quantum computer.

[so98nn]

If SHA-256 and SHA-512 can be creak by a quantum computer in the future a soft fork is enough to make crypto safe from a quantum computer.

Impossible. You will never be able to crack the SHA codes because of very obvious reason. I have already started topic regarding breaking of the SHA codes by using Quantum Computing. However after reading the responses it seems that would be impossible.

Head over here if interested in reading the same:-  SHA-256 All Possible Combination & Breaking the code Hypothesis

The topic directs how many combinations we can have and how we can break them all with the help of Quantum power.

[Myleschetty]

It is not difficult to solve this issue for the transactions in the future but those with exposed public keys will inevitably be vulnerable still.

I understand that reusing the same wallet address is not advisable when security is the top priority, the last time I read public can be share online but what you just said now makes me surprise and curious what you really mean. The question is why would people with exposed public keys be vulnerable?

[ranochigo]

I understand that reusing the same wallet address is not advisable when security is the top priority, the last time I read public can be share online but what you just said now makes me surprise and curious what you really mean. The question is why would people with exposed public keys be vulnerable?

On the similar vein, reusing address results in exposed public keys as transaction will contain the ECDSA public key of the address.

The private key can be derived from the public key using Shor's algorithm given a sufficiently powerful quantum computers. Addresses are not public keys, they are the hash of the public keys.

[suzanne5223]

If SHA-256 and SHA-512 can be creak by a quantum computer in the future a soft fork is enough to make crypto safe from a quantum computer.

Impossible. You will never be able to crack the SHA codes because of very obvious reason. I have already started topic regarding breaking of the SHA codes by using Quantum Computing. However after reading the responses it seems that would be impossible.

Head over here if interested in reading the same:-  SHA-256 All Possible Combination & Breaking the code Hypothesis

The topic directs how many combinations we can have and how we can break them all with the help of Quantum power.

I know it impossible to break SHA and if you read my statement you'll understand that I said it already but just in case a new computer was introduced in the future or a situation happen that the SHA can break happen that why I make the above statement because technology is advancing every day and what people do before are handle by bots.
Having said that, there are some people working relentlessly just to see the end of Bitcoin security.

[Hydrogen]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

AFAIK "classical computers" are optimized for multi tasking, user interface -- areas other than pure high speed number crunching. For these reasons an intel or AMD desktop CPU will emphasize integer (whole number) operations.

GPUs, ASICs and supercomputers are the opposite. Optimized for high speed, high accuracy, FLOP (non integer, floating point, fraction/decimal) calculation.

Quantum computers are essentially identical to "classical computers". The main difference is modern day computers operating on binary registers capable of representing only 0 and 1. While a quantum computer in theory is able to represent a far higher number of values to give it a greater bit density per register. Quantum computers might also have a higher clock speed. The only thing missing with quantum computers is a working prototype or proof of concept which proves the technology is viable and superior to existing tech in performance and cost effectiveness.

Quantum computers will be a danger to bitcoin the day people proclaim GPUs and ASICs obsolete and begin using quantum computers instead.

True quantum computers would be like people abandoning 8 track players for ipods. The advantages would be so obvious and pronounced it would make existing technology outdated. Until that happens quantum computers are nothing but a vaporware pipe dream.

[South Park]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

For a long time people have speculated about what this will mean for bitcoin, many have made predictions where quantum computers destroy bitcoin, but we need to be honest the cryptography used in bitcoin is used all over the world in the banking industry and to protect confidential information so bitcoin will not be the only one affected, however there are already quantum resistant algorithms, so whenever it seems that the technology is getting close to break the cryptography of bitcoin the developers could update the code of bitcoin to avoid this fate.

[tinopener]

True quantum computers would be like people abandoning 8 track players for ipods. The advantages would be so obvious and pronounced it would make existing technology outdated. Until that happens quantum computers are nothing but a vaporware pipe dream.

Exactly. Just because it is possible doesn't mean it is economically expedient.

Don't forget that cars had electric engines before combustion engines.

[Cnut237]

reusing address results in exposed public keys as transaction will contain the ECDSA public key of the address.

The private key can be derived from the public key using Shor's algorithm given a sufficiently powerful quantum computers.

Yes. This is the easiest angle of attack. Asymmetric cryptography is vulnerable to a sufficiently powerful QC. Known public keys are the low-hanging fruit.
OP, this thread might be worth a read.

Whilst a viable QC of sufficient power to hurt bitcoin is likely years away, the question of how to defend bitcoin is I believe still open. A post-quantum cryptographic solution would involve everyone having to move their coins to new quantum-safe addresses. What happens to coins that aren't moved? Or that can't be moved because they are 'lost'? Should they be burned? Should they be left to be stolen by a QC, which could quite conceivably cause market turmoil, a tanking price, and prove fatal to bitcoin? There's no obvious consensus here, no easy solution.

[choechristian00]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

In 2019, the highest-paid lifeguards in Los Angeles earned up to $392,000.

A month later, a Cointelegraph article echoed my concerns, stating that powerful quantum computers could pose a challenge to all blockchains that use the ECDSA (Elliptic Curve Digital Signature Algorithm), including Bitcoin and Ethereum.

[jesselui]

One subject I have been researching for a long time is mining with quantum computers. I think there are people who do and they make a lot of money. I think I'll buy a quantum computer soon.

[Innerpumper]

I think it's affected from VGA, and some other specs like ram and memory, classic computers have process delays, also less sophisticated than quantum computers today.

[jonval21]

Artificial Intelligence next to quantum computing, although many affirm that it will not affect, it will not do it in the first instance, because it will be in phases, the first phase or first generation of quantum computers or quantum technology will not have as much advance or as much scope , but as it improves if it will have a greater and greater impact, the technology will advance and improve each system, it may cause changes in the vulnerabilities that are seen in the future.

[franky1]

vulnerable??
its been 12 years where an address has exposed its publickey a few times
there is 18coins $1.08mill up for grabs... but so far no one has managed to take it

https://www.blockchain.com/btc/address/12cbQLTFMXRnSzktFkuoG3eHoMeFtpTu3S

seems secure to me

[CarnagexD]

Quantum computers can make and break the cryptocurrency industry. On one hand, faster computing power means easier mining, at least for a cheaper rate than what we're at right now. GPUs wouldn't be scalped anymore, so the PC gaming industry is kept alive and is not consumed by the greed of the scalpers. On the other however, private keys being hacked and sold in the black market will be more common. Since a computer that can literally guess every combination will be powerful enough to guess everyone's private key.

[DarkDays]

Quantum computers can make and break the cryptocurrency industry. On one hand, faster computing power means easier mining, at least for a cheaper rate than what we're at right now. GPUs wouldn't be scalped anymore, so the PC gaming industry is kept alive and is not consumed by the greed of the scalpers. On the other however, private keys being hacked and sold in the black market will be more common. Since a computer that can literally guess every combination will be powerful enough to guess everyone's private key.

Agreed. Quantum computer's effect on crypto and in particular Bitcoin will be massive. It will help with token mining which is getting more and more complex to solve with each minted BTC.

Apart from that, the technology breakthrough will help in solving lots of problems like climate change, AI etc...

[Grafen]

How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

Question: How will Quantum computing affect Bitcoin?
Answer: Quantum software will appear for crypto hacking

[gabriela1999]

I also read some articles about quantum computers and it would greatly affect Bitcoin or Crypto world. But I know producing a quantum computer quite expensive, very high cost. And the current quantum computer has not been widely used, and will it really affect the cryptographic money? That has not been proven. So you don't need to worry about quantum computers

[mediaBuzz]

The elliptic curve formula that is used in generating a public key from a private key is actually not a one-side equation. Because it is too difficult to calculate and it would take millions of years, it is considered to be "impossible". But the technology that quantum computers use can theoretically calculate a private key out of a public key and this is not a random thought of mine.

[ranochigo]

vulnerable??
its been 12 years where an address has exposed its publickey a few times
there is 18coins $1.08mill up for grabs... but so far no one has managed to take it

https://www.blockchain.com/btc/address/12cbQLTFMXRnSzktFkuoG3eHoMeFtpTu3S

seems secure to me

A better example would be the million Bitcoins that Satoshi has (presumably) mined and never moved.

It is secure, for now. If you can get to a sufficient qubit, you would reduce the complexity of the operations to 128^3. It'll be secure if quantum computing doesn't get any more advanced, but that simply won't be the case.

[yhiaali3]

Quantum computers have tremendous capabilities compared to ordinary computers, they have enormous speeds millions of times higher than ordinary computers, this is theoretically capable of attacking the Bitcoin network, but it is still theoretical until now and has not been actually used, I think that efforts have already begun to confront this possibility and there will be what Anti-quantum is called in the sense that there will be technologies that make it impossible for quantum computers to attack a blockchain.

[choechristian00]

We don't know the current peak capability of quantum computing as it is still in its early stages but one thing is sure that it will be a problem for bitcoin because as what is on the paper says about quantum computing, it will be far faster than any computer in the market and in any laboratories. We also have to stop telling people that quantum computing will be able to hack the private key of everyone, yes it has faster calculations but that doesn't mean that it will crack the key in a matter of days, if right now the current brute force duration is the heat death of the universe, maybe with quantum computing, the time it takes will be cut in half but that is still a whole lot of millennia.

Cryptography and quantum computers

A lot of digital ink has been spilled on how quantum computers pose an existential challenge to asymmetric cryptography as it is commonly used. As a result, we will not go into great detail about this, instead focusing on the aspects that are important to the analysis in this article.

A private-public key pair is developed in asymmetric cryptography in such a way that the two keys have a mathematical relationship. The private key is kept private, while the public key is made publicly accessible, as the name implies. Individuals can use their private key to create a digital signature that can be validated by someone with the corresponding public key.This system is widely used in the financial industry to prove transaction validity and honesty.

Asymmetric cryptography's security is founded on a mathematical concept known as a "one-way trick."The public key can be easily obtained from the private key, but not the other way around, according to this theory. All known (classical) algorithms for obtaining the private key from the public key take an astronomical amount of time to complete and are therefore impractical.However, in 1994, the mathematician Peter Shor published a quantum algorithm that can break the security assumption of the most common algorithms of asymmetric cryptography. This means that anyone with a sufficiently large quantum computer could use this algorithm to derive a private key from its corresponding public key, and thus, falsify any digital signature.

[Welsh]

Question: How will Quantum computing affect Bitcoin?
Answer: Quantum software will appear for crypto hacking

Highly unlikely at least for a while. Its been discussed so many times its almost becoming tedious. Quantum computers which are actually designed to break algorithms don't only apply to Bitcoin, but apply to everything that implements those algorithms. That's including banks, Google, and whatever else you can think of. However, quantum computers aren't particularly good at everything, they are designed to be good at one thing in particular. Therefore, to own a quantum computer which needs to be stationed in a controlled environment isn't likely going to fall into the hands of criminals, unless of course you consider the government to be criminals.

The government, military, and potentially high profile companies are the only ones that would be able to afford quantum computers, and even then a smaller division of this number will actually have a need for quantum computers. I would say that the government, and military are the only ones which could justify the cost. Now, you could say that the government are hostile towards Bitcoin, but that entirely depends on the government your talking about. Many governments have actually successfully regulated Bitcoin, and therefore Bitcoin earns them more money than not having it. By breaking Bitcoin if that was even theoretically possible would actually reduce the amount of money they earn. Bitcoin, isn't likely to replace fiat currencies, at least not for a long time. In fact, Bitcoin is probably not something that would replace it, but a similar implementation of Bitcoin might. Therefore, Bitcoin in its current state is of limited threat, and actually benefits the governments that have successfully regulated it.

By the time, Bitcoin was to become a threat or quantum computers became affordable enough to own for others, Bitcoin as well as banks, and other big industries would have already implemented quantum resistant algorithms, effectively making it redundant.

Quantum computers aren't even particularly good for hacking, they are good at breaking a specific type of algorithm, and wouldn't be able to be used for anything other than that. The biggest benefit of a quantum computer is using it in the military for obvious reasons.

Peter Shor published a quantum algorithm that can break the security assumption of the most common algorithms of asymmetric cryptography. This means that anyone with a sufficiently large quantum computer could use this algorithm to derive a private key from its corresponding public key, and thus, falsify any digital signature.

Which just to be clear;

1. We are fair bit off a quantum computer being able to achieve the level of qbits required.
2. Barely anyone would be able to afford it.
3. Even if they could afford the quantum computer, and be able to run it highly unlikely they wouldn't be able to justify the costs.

[ranochigo]

The government, military, and potentially high profile companies are the only ones that would be able to afford quantum computers, and even then a smaller division of this number will actually have a need for quantum computers. I would say that the government, and military are the only ones which could justify the cost. Now, you could say that the government are hostile towards Bitcoin, but that entirely depends on the government your talking about. Many governments have actually successfully regulated Bitcoin, and therefore Bitcoin earns them more money than not having it. By breaking Bitcoin if that was even theoretically possible would actually reduce the amount of money they earn. Bitcoin, isn't likely to replace fiat currencies, at least not for a long time. In fact, Bitcoin is probably not something that would replace it, but a similar implementation of Bitcoin might. Therefore, Bitcoin in its current state is of limited threat, and actually benefits the governments that have successfully regulated it.

By the time, Bitcoin was to become a threat or quantum computers became affordable enough to own for others, Bitcoin as well as banks, and other big industries would have already implemented quantum resistant algorithms, effectively making it redundant.

If the country's primary goal is to evade sanctions and improve financially instead of espionage or anything similar, they'll probably opt to attack Bitcoin. I'm pretty sure North Korea isn't developing quantum computer though. If not, then I think most countries would just start with deciphering the encrypted communication.

The problem with quantum computers isn't with the kinds of algorithm that we could move towards in the future but the exposed public keys which would be inherently vulnerable even after the network forks to a new algorithm. Do you burn them or do you just leave a few million Bitcoins to be able to be exploited. Sure, quantum computers are expensive and the cost/benefit doesn't add up but as time goes by, these Bitcoins could eventually be a suitable target. You won't know if anything was broken by ECDSA; spending the 50 Bitcoins from the exposed addresses could just very well mean that whoever controls the private keys wanted to spend them.

[Welsh]

If the country's primary goal is to evade sanctions and improve financially instead of espionage or anything similar, they'll probably opt to attack Bitcoin. I'm pretty sure North Korea isn't developing quantum computer though. If not, then I think most countries would just start with deciphering the encrypted communication.

The problem with quantum computers isn't with the kinds of algorithm that we could move towards in the future but the exposed public keys which would be inherently vulnerable even after the network forks to a new algorithm. Do you burn them or do you just leave a few million Bitcoins to be able to be exploited. Sure, quantum computers are expensive and the cost/benefit doesn't add up but as time goes by, these Bitcoins could eventually be a suitable target. You won't know if anything was broken by ECDSA; spending the 50 Bitcoins from the exposed addresses could just very well mean that whoever controls the private keys wanted to spend them.

Okay, so this is probably the only legitimate counter argument that could be presented that's for quantum computers becoming a risk to cryptocurrencies, and I can't really argue that fact except for; By the time quantum computers come available which are capable of breaking the ECDSA, I'd expect us to have a solution via a quantum resistant algorithm already implemented. Of course, this would require a fork, and not everyone would be willing to move or some people aren't going to move. At that point, you'd probably expect that a lot of coins would be available to target, but if we have enough notice, and good enough reasons to fork then I would expect the majority of people would move their coins to the quantum resistant algorithms.  

So, this just leaves the coins which have been lost prior, those that didn't want to move, or those that didn't hear about the fork. These are risks, and unfortunately will happen when it comes to it. These coins could be targeted, however if they've been given good enough reason to move, and enough timeframe then they themselves are taking the risk of leaving their coins there. So, they accept the risk of losing them.

That being said, when this does happen the affordability still comes into consideration. If its only high profile companies, and governments that have access to quantum computers capable of breaking ECDSA, then they aren't likely to be interested in coins that have been left. First of all, there's no real motive. The issue is when quantum computers become accessible to your common criminal, those are the ones which would more than likely be interested in targeting these coins, but by the time that happens there will be enough notice, and will allow people to weigh up the pros, and cons.

I don't think in the grand scheme of things, its a major issue. There's multiple factors which have been mentioned above which will delay the threat of quantum computers, which should allow adequate time for planning, and implementing a solution, and having those that having doubts about moving to a different protocol, time to make up their minds.

We could burn them, given enough notice that does seem very extreme though, and I'm not sure that's the best decision. Undoubtedly, any coins that are left that can be exploited, will likely be exploited eventually, and that would likely have an effect on the short term value of Bitcoin.

[ranochigo]

Of course, this would require a fork, and not everyone would be willing to move or some people aren't going to move. At that point, you'd probably expect that a lot of coins would be available to target, but if we have enough notice, and good enough reasons to fork then I would expect the majority of people would move their coins to the quantum resistant algorithms.  

So, this just leaves the coins which have been lost prior, those that didn't want to move, or those that didn't hear about the fork. These are risks, and unfortunately will happen when it comes to it. These coins could be targeted, however if they've been given good enough reason to move, and enough timeframe then they themselves are taking the risk of leaving their coins there. So, they accept the risk of losing them.

We could burn them, given enough notice that does seem very extreme though, and I'm not sure that's the best decision. Undoubtedly, any coins that are left that can be exploited, will likely be exploited eventually, and that would likely have an effect on the short term value of Bitcoin.

Most of Satoshi's block rewards are vulnerable; Bitcoin Core was configured for P2PK in the Coinbase transaction and that makes up for approximately a million (IIRC) of his coin or at least those that weren't moved or presumed lost/burned. Considering that each address has 50 coins, and at current prices, that would be north of 3 million per address. That is assuming Bitcoin doesn't grow further than 60K, which is hard to tell. The economic impact of losing that many coins won't bode well.

[lifeforcepools]

Now is not the best time to think about quantum computers. Let's solve the problems that we have now.

[Welsh]

Most of Satoshi's block rewards are vulnerable; Bitcoin Core was configured for P2PK in the Coinbase transaction and that makes up for approximately a million (IIRC) of his coin or at least those that weren't moved or presumed lost/burned. Considering that each address has 50 coins, and at current prices, that would be north of 3 million per address. That is assuming Bitcoin doesn't grow further than 60K, which is hard to tell. The economic impact of losing that many coins won't bode well.

From a economic point of view, yeah that would likely have disastrous economic short term effects, but I'm not entirely sure that long term effects would be negative. If they were to be stolen, and we don't consider the morality in that right now, it would mean that there's more coins in circulation, which depending on what point of view your looking at might devalue the amount of coins, because as you know some people treat lost coins as "donations" to the network.

I'm still convinced, it will be a very long time until anyone with a motive to do it i.e common criminals, will be able to access quantum computers. I'm not convinced that the government, whatever that one might be would have any real motive. I think we like to think they're threatened by it, but I don't think in its current state it is.

I don't know the ideal solution, ideally we should never really assume coins that haven't been moved for a very long time, are "lost" so "burning" them without permission from its owner doesn't quite sit well with me. So, now to move onto the ethics of dealing with this scenario; is it better to burn the coins without permission in an attempt to better everyone else using the currency or is it better to allow those coins to be attacked, despite their owner having lost them, whether that's through choice, mistakes or not being around anymore. Its something which will need a decision, but quite frankly I'm not quite sure what's the correct way of going about it, obviously this has been brought up a lot over the years, and I think most would lean to the greater good, but I'm not a big fan of that viewpoint.

This is why I'm hoping people far brighter than me are in charge of this decision. I don't know the true economic damages that something like this would cause. If its just short term, which I believe short term would be the worse of the two, then that isn't so bad for a currency. If it has longer term effects, that could be detrimental to the survival of the currency (which I find implausible) then that's something that I imagine that needs to be taken into consideration. Even then though, burning coins that don't belong to you doesn't bode well with me. My question, and this might be more of a rhetorical question is; does anyone really know the true implications that it would have on Bitcoin?

[Twentyonepaylots]

Miners and hackers will be the ones to benefit the most about the public release of Quantum Computers. Their theoretical power is enough to ensure that no GPUs will be needed anymore in mining. Thus reducing the chances of GPU Scalping as well, keeping the PC gaming industry alive. On the downside however, hackers getting a hold of quantum computers will make it incredibly easier for them to tap into virtually everyone's private addresses, so hacking and stealing bitcoins will be regular news to us.

[Argoo]

I also read some articles about quantum computers and it would greatly affect Bitcoin or Crypto world. But I know producing a quantum computer quite expensive, very high cost. And the current quantum computer has not been widely used, and will it really affect the cryptographic money? That has not been proven. So you don't need to worry about quantum computers

Of course, quantum computers will have a big impact on the existence of cryptocurrency. An increase in computing power will have both a positive effect on its mining and a negative effect on the possibility of breaking our secret keys. However, we will definitely be able to find out when they appear enough for us to see the practical results of their capabilities.
As for their expensive cost, then with their mass production and the improvement of their production, their value will fall. I have already read that quantum computers of low power are installed in schools in China to study their principle of operation and capabilities.

[Obito]

I never really pondered on this topic of qantum computing since I won't be alive when it becomes available for personal use. So my answer to that is that quantum computing is only going to be a threat to bitcoin if it becomes available for public use, I think right now we don't have to worry about it because they don't even have the complete understanding of it so don't wrap your beads too much about it.

[nebuch]

For me quantum computer seems complete to solve many issues including blockchain. However I think we cannot yet say the accurate thing what quantum computer can actually do. The actual scenario matter before we can conclude that quantum computer will effect bitcoin and Cryptos because of this and that and so on.... Let us wait further official launching which I think it takes more time as it is complex.

[choechristian00]

It has been explained to me, albeit, in layman's terms, that one of the reasons our modern cryptography works so well on classical computers is that they rely on prime factorization which classical computers don't do so well. This has been key to maintaining our computers and networks secured. One of the things Quantum computers do better than classical computers is prime factorization. How will the advent of Quantum computing impact cryptography? Will technologies like blockchains and bitcoin be affected?

In the cryptocurrency community, there is a nagging fear of quantum computing. Is it possible that it can decrypt cryptocurrencies and the encryption that protects them? I'm not sure how close that is. Do the headlines about "quantum superiority" imply that my personal information is at risk?

The short answer is no. But let's take a closer look at this phenomenon and try to figure out why this is the case and how quantum computing works.But let us delve a little further into this phenomenon to see why this is the case and how quantum computing can deal with cryptocurrencies.

To begin, let's describe quantum computing and the classical computing we're all familiar with, and see how the two terms compare and contrast. Quantum computing is similar to “classical” pre-computer computing in terms of paradigm.Quantum computing is approximately equivalent to "classical" pre-1900s physics and "modern" physics, which includes Einstein's relativity and quantum physics insights.

As a result, quantum computers are not uniformly better than classical computers, which will be immediately important to the debate. When people talk about "quantum dominance," as stated by Google GOOG -2.4 percent and/or China, they just mean that a quantum machine will perform a task better than a classical computer, possibly one that is impossible to perform for any purpose.