Bitcoin and Quantum computer

[Lauda]

if bitcoin switch to a new algorithm, what will happen toall the chinese miner?

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

also this need a hard fork right? chinese will never agree on this hard fork, they would lost millions

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'.

Qunatum computers are like unicorns. Everyone knows they exists but noone saw them.

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

it support encryption for wallet

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.

[1715454260]

1715454260

[zimmah]

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/

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.

[Foxpup]

Correct, such a change does require a hard fork.

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.)

[Lauda]

Correct, such a change does require a hard fork.

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.

[kidayb@sina.com]

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

[CIYAM]

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.

You do realise that Bitcoin doesn't use encryption?

it support encryption for wallet

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?)

[n691309]

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

[~Bitcoin~]

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/

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.

[jackg]

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.

You do realise that Bitcoin doesn't use encryption?

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.

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.

[n691309]

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.

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.

[Lauda]

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.

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).

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.

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.

[jackg]

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.

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.

[BADecker]

Quantum Computers Will Make Even "Strong" Passwords Worthless

The race is on to perfect quantum computing. It will make your bank passwords and all existing security methods useless.

The Hutch Report has a fascinating 44-page PDF on Quantum Computing.

If perfected, existing methods of encryption will cease to work. Your bank account password and passwords to cryptocurrencies will easily be hackable.

The ability to break the RSA coding system will render almost all current channels of communication insecure.

This is a national security threat.

The benefits are also huge: Quantum computers will be superior at hurricane detection, airplane design, and in searching DNA for markers to help find cures for diseases such as Autism, Alzheimer's, Huntington's, and Parkinson's.

Classical Computers

Classical computers use strings of 0's and 1's with a single digit a "bit" and strings of bits a "byte". A bit is either a one or a zero.

Excerpts from the Hutch report now follow. I condensed 44 pages to a hopefully understandable synopsis of the promise and problems of quantum computing.

Quantum Background

Quantum computing does not use bits, but uses qubits which can be one, zero, or both zero and one at the same time. This state or capability of being both is called superposition. Where it gets even more complex is that qubits also exhibit a property called entanglement. Entanglement is an extraordinary behaviour in quantum physics in which particles, like qubits, share the same state simultaneously even when separated by large distance.

As comparison a classic computer using bits of zero and one can only store one state at a time and can represent 2n states where n is the number of bits. In the case of two bits, this would be 2*2 which is four states: 00, 01, 10, 11.

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

[Ozero]

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.