Bitcoin Forum

Hello,
Quantum computer can break all algorithm of cryptography in just a second.
So what will happen to Bitcoin algorithm?

http://hackaday.com/2015/09/29/quantum-computing-kills-encryption/

Absolute nonsense.

I know Arthur C. Clark has said:
"Any sufficiently advanced technology is indistinguishable from magic"

But that doesn't mean it actually is magic.

Just because you personally don't understand quantum computing, it doesn't mean that it can instantly put an end to anything that you might imagine.

Some algorithms will become weaker.  Some won't.  If any of bitcoin's algorithms become weakened a bit, then we can switch to more quantum resistant algorithms.  If they aren't weakened, then we'll just leave them the way they are.


Which one?  Most of them will be just fine.  Those that aren't (if any) will be swapped out for something else.

yeah yeah, nada nada.  heard it all before lets make a working quantum computer first and then we will discuss this theory....... ::)

Quantum computing claim that factoring can be speed up many many times. This is the base of public private key.

I love this! Would it just be bitcoin that would be at risk? The whole OSI layers and protocols/internet (banks/ATM/[insert name]) would be at risk. I'm sure quantum cryptographical algorithms would be created by the IETF (https://en.wikipedia.org/wiki/Internet_Engineering_Task_Force) to maintain a swift & smooth move, when the internet enters this era.

http://www.bitcoinnotbombs.com/bitcoin-vs-the-nsas-quantum-computer/

 (http://www.bitcoinnotbombs.com/bitcoin-vs-the-nsas-quantum-computer/)

and

https://www.google.com/search?q=Post-quantum_cryptography&ie=utf-8&oe=utf-8&gws_rd=cr&ei=nVhTV8jkBYmpjwS5wo3YDA#q=Post-quantum+cryptography+and+bitcoin (https://www.google.com/search?q=Post-quantum_cryptography&ie=utf-8&oe=utf-8&gws_rd=cr&ei=nVhTV8jkBYmpjwS5wo3YDA#q=Post-quantum+cryptography+and+bitcoin)

As long as governments are pissing and moaning about encryption and trying to get it outlawed for us regular folk to use, you have nothing to worry about.

Bitcoin doesn't use RSA, so factoring is unrelated. However, it is claimed that quantum computing can speed up discrete logarithm calculations (https://arxiv.org/abs/quant-ph/9508027) to polynomial time, which may hypothetically jeopardize the EC signature aspect of Bitcoin. However, because addresses are pubkey hashes until spent, if addresses are never re-used after spent from once, and a transaction from an address moves all coins to a new address, then the pubkey is still protected by being hashed (which AFAIK doesn't have an efficient quantum-computing weakness, save for Grover's algorithm, which doesn't provide that much of a benefit).

Once they actually get a quantum computer to work that isn't just "well we have he concept and the hardware, but it hasn't been able to perform X action", then I'd make finding a new algorithm a bigger priority, but for right now if they only have a few quantum computers in the world and they're in the hands of specialists, and I won't worry. Once quantum processors come out for civilian use is when it would be a bit late to find a new algorithm.

I was fairly confused by the idea that "quantum computers can break Bitcoin"
They are said to run algorithms faster, that could mean an increase in domestic mining and more decentralisation of the coin if adapters are put in place to change from binary to qubit (I think that is what is is known as).
They are also said to be able to therefore "crack" algoritms at greater speeds offering damage to the Bitcoin network, though this should be fixed by the current development team of Bitcoin.

I don't think quantum computers are going to decentralize Bitcoin, especially while they are still inaccessible to the general public (due to high upfront costs, specialized equipment such as cryogenic cooling, etc). Likewise, the idea of an "adapter" between binary and qubit doesn't make sense--a qubit is a component of a quantum computer used when performing a quantum computation, storing a superposition of typically binary values, if I'm not mistaken. All that simply would be needed is a classical-computing controller that provides the inputs to the algorithm used and transfers them over some medium to the quantum processor.

Banks rely on the same technology used by Bitcoin. If quantum computers broke Bitcoin they would also break banks with control over far bigger amounts of money than Bitcoin's market cap. They haven't developed quantum computers advanced enough to do that yet, and they are making improvements to crypto to ensure it remains reliable when advanced quantum computers are developed.

First of all, we have no such tech yet. And I doubt we will see it during our lifetime. So far we have big words and researchers claiming that it will be done.
And people tends forget about 2 things:

1. Bitcoin's security was designed to be upgraded so if we will face the possibility of quantum computers threat - bitcoin security will be upgraded, no need to worry.
2. Bitcoin is not the best target for someone who would like to steal a lot of money -  primary target are financial institutions: banks, currency and stock exchanges, etc.

Fall in this case means "be weaker" and not "can be cracked within seconds".


Mining is not affected, as Danny already said some algorithsm can not be solved quicker with quantum computers.


Dont refer to search results if you want answers.

When encryption cracking becomes easier, someone will figure out a way to make a new encryption method that is resistant to the new method.

In case of quantum computing, if it ever becomes viable at cracking 256-bit encryption, bitcoin can easily switch to a different encryption or multi-layered encryption method.

Quantum computing may sound scary, but there are a lot more parties with much more to lose than bitcoin. Just imagine banks and security agencies... They will never allow their systems to be cracked.

You do realise that Bitcoin doesn't use encryption?

if bitcoin switch to a new algorithm, what will happen toall the chinese miner? also this need a hard fork right? chinese will never agree on this hard fork, they would lost millions

Qunatum computers are like unicorns. Everyone knows they exists but noone saw them.
Simple as that ;), hope u understand deeper meaning.

it support encryption for wallet

The OP is talking about obtaining private keys from the blockchain via brute force.

Adding a password or having a password free wallet has nothing to do with this topic or this context. Those are personal preferences.

That depends. There's no definite answer to that question.

Correct, such a change does require a hard fork. The "chinese" (as in the miners located in China) don't have to agree on anything (the other option carries the loss of everything anyways). It seems like some think that these guys have control over the network. People need to stop panicking when they hear the words 'quantum computers'.

Just because you haven't seen them, that does not mean that you should make such hasty generalizations.

That's a whole different story. Besides, in order to be able to do something about wallet encryption they'd have to gain access to your wallet file.

there are already algorithms that are quantum proof, we'd just update the bitcoin algorithm to be quantum-proof, and done.

Even if they did breach bitcoin before we change the algorithm, since the blockchain records all history since the beginning, we can just roll-back all transactions until just moments before the attack, and use that as the official blockchain and start from there.

Wait, what? The only change is that ECDSA needs to be replaced with something quantum-resistant, and I thought that new signature algorithms were a soft fork? (And that SegWit makes such updates easier, but that's another topic.)

He asked about a switch to a new algorithm (mining), i.e. changing SHA256. At least, that's how I understood the question, I might be wrong though.

I think this is an interesting topic, but I think with the increase in the calculation of the same difficulty is rising so we do not have to worry about

You do realise that "wallets" have absolutely nothing to do with the Bitcoin protocol?

(this poster wasn't a supposed Legendary forum member and doesn't have an ad-sig so can be excused I guess but first poster is clearly a bought account - although I do wonder if the former wasn't perhaps bought by the latter?)

I think that we should not worry about quantum computers breaking the bitcoin for at least 20+ years from now because it need too much time to break a bitcoin key. I have read an article posted from theymos [1] which explain in detail about this phenomenon.

[1] https://en.bitcoin.it/wiki/Quantum_computing_and_Bitcoin

This is just a hypothetical computer, this quantum computer will take more than centuries from now to be publicly available to purchase or even more time than this. But i have also read somewhere that bitcoin network will be forked to make it unbreakable with quantum computer when they will be in the market. I am not seeing any quantum computer to exist in working model till next one or more centuries.

I have a solution - Increase the size of the private keys!
If we increased them to a large size such as 1GB then there would be very little that quantum computers could do to crack these keys as they would be too big in their combination sizes.
I know that 1GB in comparison to the blockchain's size is not much of a problem.
It would be good if you could customise the size of the private keys but the network would have to adjust itself slihtly.

From the link that i pasted above seems that to break a bitcoin key it is needed a quantum computers that has at least 1500 QuBits, but until now there are up to 10 QuBits. It is not only dangerous for bitcoin but also for banks which use different decryption method which can be decrypted by these computers.

The current private keys are usually 256-bit (although there are wallets that tend to create them with different sizes). What you're talking about is a size of 1 GB per key which is a exponential increase in comparison to what is currently being used and highly inefficient. If the hashing algorithms behind the process get 'broken', increasing the key size is not the right answer (they'd possibly just need to spend more time per key or get more computational power).

They seem to think that, but that is the theoretical requirement at this point and we do know that things tend to differ a lot in theory and practice.

There is also a very big difference between 10QuBits and 1500QuBits.
Banks that get the highest qubit computer will still be ahead as they have more money to spend on it so they can produce more complex alogrithms before others anyway.
If we think that quantum computers have been known for over 10 years and we have now got one that is at 10QuBits then it will take a very long time to get to 1500QuBits.

Quantum Computers Will Make Even "Strong" Passwords Worthless (http://www.freedomsphoenix.com/News/236362-2018-03-13-quantum-computers-will-make-even-strong-passwords-worthless.htm)


https://www.freedomsphoenix.com/Uploads/Graphics/693-0313085104-Quantum-Computer.jpg (http://www.freedomsphoenix.com/News/236362-2018-03-13-quantum-computers-will-make-even-strong-passwords-worthless.htm)




Read more at https://www.themaven.net/mishtalk/economics/quantum-computers-will-make-even-strong-passwords-worthless-9TyMxlg6gEiUhY99nJio2A.


8)

I see that the security problem of crypto-currency in the event of the emergence of quantum computers still exists. It should take into account the possibility of their limited use by individuals or even state structures of individual countries with a hacker's aim. This can inflict enormous damage on the economies of selected countries before a protective response is taken. I think that there are already many developments in this direction.