Topic: Hackers/Public will have Access to Quantum Computers in 5-10 years? (Read 498 times)

o_e_l_e_o has already answered it in the best way possible. And even if it may not take "centuries" as he claimed, I would say that we are safe for at least the next 10-15 years. And by some miracle if it happens earlier, then all it takes is a hard fork to change the SHA-256 algorithm to something more secure. Some of the altcoins may be impacted in the future by the advance in quantum computing. But I don't really foresee any real challenge to Bitcoin. If the status quo remains for another 10 years, then it will be enough for me.

The value absolutely does change. Light propagates at different speeds in different medium, and different wavelengths of light also propagate at different speeds in those medium. In the most simple example, that's how a rainbow forms - from the different wavelengths of light from the sun propagating at different speeds through water droplets.

Quantum computers make some specific things which are simply too difficult with standard computers much easier, but they can not solve any and every problem, such as turning an address back in to a private key.

No, it isn't. It will be possible in select cases as we've discussed above, but even when finally possible, will still take a prohibitively long time for many years until quantum computers are much improved.

CBDCs will be entirely centralized, and so there is zero trade off for them to implement quantum resistant algorithms.

Not really programmed from the start, it is an observation.
Quantum isn't like a silver bullet, it still obeys physics but it's just that it is not immediately clear what we can do with it. The issue here is with the recovery of PK keypairs, and no one is denying that it is possible. We have proven that Shor's algorithm is able to factor integers far faster than classical computers. I don't think that it isn't possible in the distant future, but that it would be so expensive that people wouldn't bother with it. By then, most would've shifted to a different algorithm or the remainder *could've* also been burned.

Those quantum corporations are owned by the big tech giants such as google, Microsoft and such. If they do decide to attack bitcoin then the bitcoin community will know who to blame and the reputation of these tech giants will fall as they engaged in illegal hacking crimes.

---

Normal legacy physics and maths and computing is based on certainty, logic, truth equation, predictable patterns and such.

For example speed of light is a constant 299,792.458 km per second. This value never changes always the same as its like its has been programmed to be from the start and never goes below or higher than it. Its certainty. Light can be measured in waves and frequencies and these are predictable repeatable patterns.

Quantum is the weird opposite stuff as its uncertainty, unpredictable, the impossible. Like a light switch being on and off at the same time yet the light is on and off at the same time. Sounds impossible I know but Quantum is making impossible seem the possible.

500 years ago if anyone has said the world is round then you would have been called crazy mad lol.

If Quantum can do the impossible then getting private keys is a walk in the park for quantum.

Quantum is just not a threat for Bitcoin its a threat to Central Banks upcoming CBDC's too.

I wonder how governments & central banks are preparing against quantum computers that are a threat to their CBDC's?

I believe not far in the distant future Quantum computers will recover the lost bitcoins in the dead btc wallets.

[moderator's note: consecutive posts merged]

No. Not every calculation is the same. Some calculations would be exponentially faster with a quantum computer, some would be linearly faster, and some wouldn't be faster at all.

Turning a public key in to a private key is particularly susceptible to quantum computers. A quantum computer running what is known as Shor's algorithm could reduce the number of operations required from 2¹²⁸ to somewhere in the region of only 128³. This number of operations is trivial for a standard computer, and so quantum computers will eventually reach this stage also.

However, reversing a hash and calculating a public key from an address would only experience a linear speed up. The best method for doing this, Grover's algorithm, only reduces the search space for SHA256 from 2²⁵⁶ to 2¹²⁸. 2¹²⁸ is simply too large a number to be threatened by any computer, quantum or otherwise. The entirety of bitcoin is built on security of 2¹²⁸, and nothing has ever come even close to a tiny fraction to the number of operations required to break it.

But wouldn't the quantum computers be able to decipher the hash of those private keys? Because they're made to make calculations that could last for about a million years to be solved shortened in a matter of seconds, will it be a threat?

They will difinetly have access to them in 10-15 years or so. And I dont know what we all wil do about encriptions in our life

I think it is a very interesting topic that needs to be discussed further and it would be useful if there is a resource person who was knowledgeable enough about quantum computers. Anyway base on the reply's above many tech-savvy forum users are sharing their knowledge about quantum computers so it's a very useful OP,

Anyway, IMO, If quantum supremacy was already achieved ( because I doubt it personally) I think they need much time to improve it and develop further to make them more powerful enough to crack even a single private key, sounds futuristic right? but believe me, it is not an easy task to do. thats why I believe it has no reason to be alarmed about quantum computers.

All addresses, be they legacy or segwit, are derived from hashes of the public key. It is only very early transactions which used P2PK - pay to pub key - which do not use hashes of the public key and would be inherently vulnerable to quantum computers. All addresses in current use are only vulnerable if they have already made an outgoing transaction and therefore revealed their public key.

OP, tell me something.....

You are saying that there are a few quantum computers in existence today... So tell us, how many of these quantum computers have successfully acquired even 1 Private Key? This would have been blasted on all news media platforms ..if that was true.... but it is not true. It is not as if it is not productive to do this, because 1 000 000 of Satoshi's coins are still out there... so if they can do this, then they can cash in on a major treasure.

Even if they are successful ..some time in the future, then developers will fork to a new coin with stronger encryption and people will just shift their coins or use the new forked coins. (Full nodes will just be too happy to allow this, because it will protect their coins) 

This is not a good thing. First, it would be stealing from those people. There is no guarantee that any of them have lost access, no matter what people believe. Very early bitcoin was filled with tinkerers and people who believed in its vision. If you put a key into cold storage for 10-20 years, then should others be allowed to take it?

Second, it would make bitcoin useless. If there is no security and ability to verify owners with private keys, then there is no bitcoin and no cryptocurrency. It removes a significant independent voice within finance.

As for whether it's possible, bitcoin uses two algorithms for signing. While private-public key pairs will be more easily determined, I believe that segwit resolves this by obscuring the public keys behind hashes, which hashing function is much more efficiently solved by non-quantum computers -- and still takes quite a long time. This does mean that the owners of very dormant addresses may have limited time to move their keys to new addresses if the public key is known, but it should provide no difference to addresses without publicly known keys.

Quantum ASICs don't protect against quantum computers attacking individual key pairs, though. If we ever get to the stage where quantum computers can solve the discrete logarithm problem in a reasonable amount of time and calculate a private key from a known public key, then it doesn't matter what hardware is securing the network - we will need to fork away from ECDSA to a quantum resistant algorithm. This is entirely doable, and for most people would simply mean moving their coins to a new address type, as we have already done with segwit.

And even when we finally get a quantum computer capable of breaking ECDSA, it will still take it weeks or months to reverse a single public key. It will be decades more before they are fast enough and powerful enough to do so in <1 hour and consider attacking a public key which has only been revealed for the first time when a transaction has been made.

Willing to bet that we will be seeing the exact same subject line for posts 10 years from now 
In short - not gonna happen in this decade. From the research articles I've read we are still a long way from running any sort of complex programs that go beyond simple math exercises.

This is a very interesting article. It is also scary as we do not know if these computers are capable of exploiting the blockchain or by making sabotage the mining industry by creating 51% attack. We do not what will happen next. But I doubt their claim of getting anyone's private key in a fraction of seconds.

They aren't true quantum computers. The number of qubits isn't of any significance if they cannot be used to achieve what we need. The current quantum computers that you see, ie. by DWave claims to have a fairly high qubit but the technology that they're using to achieve it is quantum annealing. Quantum annealing cannot run Shor's algorithm to achieve the exponential decrease in the time taken. They are used for entirely different applications, universal gate QCs are the ones which are of concern.

Thanks for the knowledge. As far as I know, there are several quantum computer (or I should call quantum processor) in the world right now and they have been proven to solve problems which can only be done by them (quantum supremacy). But it is true that only some specific field that quantum computers are faster than supercomputer

Well, quantum algorithm might be the solution when there are thousands of quantum computer existing. They will surely enhance the strength of bitcoin and its private key

The day we "get" quantum computers, is the day we "get" quantum ASIC miners to balance the equation.

Tech firms seeking to develop quantum computers need funding and resources. That's where "5 to 10 years" comes from. They exaggerate and make overambitious and overzealous promises to attract investors. The technology will likely never become a reality. It shows in the 5-10 year estimate that they have no real blueprint or roadmap.

Anyone who looks into the specifics of claims made by "quantum computer developers" will see many different forms of sketchy and shady behavior. That are not found in legit peer reviewed research.

The whole quantum computer debate has been around for some time, and something I remember an Uber driving to tell me about one time.  He was going on and on about how bitcoin will be taken down by quantum computing etc.  However it seems like no one take in to consideration that the blockchain is programmable and there will be ways for the Devs to update the blockchain.  I'm not sold on Quantum being a huge deal at all.

This is a very common misconception. It is true that many of the encryption algorithms currently in use are quite vulnerable to quantum computing. But there are already some that are built in such a way that quantum computers cannot crack them. Research into this has increased enormously in recent years.

Doubt so. Even if he did, QCs were too far away of a threat that it still made sense to use ECDSA.
Maybe. Who knows?
It is a misnomer. Definition of cryptography, as specified in RFC2828 states that; The mathematical science that deals with transforming data to render its meaning unintelligible (i.e., to hide its semantic content), prevent its undetected alteration, or prevent its unauthorized use. If the transformation is reversible,cryptography also deals with restoring encrypted data to intelligible form.

Cue the bolded part which concerns Bitcoin. If you disagree, please highlight the part in Bitcoin that would prove otherwise.

Yes.