How will Quantum computing affect Bitcoin?

[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 The advantages would be so obvious and pronounced it would make existing technology outdated.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.