Do you think quantum computers would break Bitcoin's security?

[Snail2]

I guess one day when quantum computers will be standard stuff at every govt agencies and banks this going to be a real issue. Luckily quantum computing at this moment very much in it's infancy so the devs still have a couple of years (maybe decades) to find out something.

The community here also have at least a decade to agree on forking or not forking. Probably this part going to be the bottleneck .

[BillyBobZorton]

Quantum computing studies theoretical computation systems (quantum computers) that make direct use of quantum-mechanical phenomena, such as superposition and entanglement, to perform operations on data.
Large-scale quantum computers will be able to solve certain problems much more quickly than any classical computers that use even the best currently known algorithms.
In theory this kind of computing power will be unbelievably powerful and be able to achieve much greater "solving power" which could crack algorithm behind bitcoin (commonly referred as: public key cryptography).

For more information visit: http://en.wikipedia.org/wiki/Quantum_computing

Bitcoin is designed to last for over a 100 years. Obviously we don't have this kind of computers yet.
But we will be, maybe in 10 maybe in 20 years, but definitely sooner that we may think - and then, at that time bitcoin may be world currency...
So do you think quantum computers would break Bitcoin's security?

Yes, but it will take WAY longer than we'll ever live, therefore Bitcoin will be here for a long time. Longer than we can imagine. 1000's of years. Anything else is science fiction.

[Amph]

on sha256 security bit are only 128, and quantum computer can break this(i can't find the article), if today pc can break 64 quantum computer can break at least the double of that
so bitcoin will need an hard fork in the future to survive

Stop talking nonsense. Quantum computers can't break SHA256 (used for hashing) without brute forcing it unless a flaw in it has been found. There is no article to link. I'm not saying that someone won't find a way to attack it in the future though.

you are wrong it can break 128 key(the power of quantum computer is like a pc that halve the difficulty, and if today pc, tons of them, could break 64, then a quantum can break 128) this is not enough to break sha256(or the private key which is 256 bit) i know, i didn't explain it well, but it is enough to break the pubblic key which is 128 bit

Your English levels are under those of a 5th grader. Consider taking a course, because you complicate things and usually make no sense.
I never said that SHA256 for a normal computer wasn't SHA128 for a quantum one. You didn't explain it because it can't be explained well i.e. what you said effectively makes no sense. A quantum computer can't beat SHA 256 (i.e. SHA 128). Actually if SHA gets broken the problem will be on a much larger scale where Bitcoin will be irrelevant (unless globally adopted). A lot of things use SHA, for example banks.

What I'm trying to say is: For SHA256, it effectively becomes SHA128 to a Quantum computer. Now the question remains, can a Quantum search for SHA128 faster than a classical computer search through SHA256?
With out current technology and for the near future, we still can't build a real Quantum computer that can even begin to tackle this problem, let alone solve it.

i think you are not understanding, my english was clear enough in the last post you quoted, quantum computer can break any 128 key, it has been said many times, there is no question here

now, public key are 128 bit, instead private key are 256, so the first can be brute forced by any quantum computer, and if you have that key you could retrieve the private key, but this only if the targeted public key is send when you spend a transaction

here a link http://bitcoin.stackexchange.com/questions/6062/what-effects-would-a-scalable-quantum-computer-have-on-bitcoin

there are many other confirming this

[thejaytiesto]

SHA256 will never be cracked during our lifetime and beyond, this is a non issue. Efforts should be put instead in what to do with the blocksize limit.

[redsn0w]

on sha256 security bit are only 128, and quantum computer can break this(i can't find the article), if today pc can break 64 quantum computer can break at least the double of that
so bitcoin will need an hard fork in the future to survive

Stop talking nonsense. Quantum computers can't break SHA256 (used for hashing) without brute forcing it unless a flaw in it has been found. There is no article to link. I'm not saying that someone won't find a way to attack it in the future though.

you are wrong it can break 128 key(the power of quantum computer is like a pc that halve the difficulty, and if today pc, tons of them, could break 64, then a quantum can break 128) this is not enough to break sha256(or the private key which is 256 bit) i know, i didn't explain it well, but it is enough to break the pubblic key which is 128 bit

Your English levels are under those of a 5th grader. Consider taking a course, because you complicate things and usually make no sense.
I never said that SHA256 for a normal computer wasn't SHA128 for a quantum one. You didn't explain it because it can't be explained well i.e. what you said effectively makes no sense. A quantum computer can't beat SHA 256 (i.e. SHA 128). Actually if SHA gets broken the problem will be on a much larger scale where Bitcoin will be irrelevant (unless globally adopted). A lot of things use SHA, for example banks.

What I'm trying to say is: For SHA256, it effectively becomes SHA128 to a Quantum computer. Now the question remains, can a Quantum search for SHA128 faster than a classical computer search through SHA256?
With out current technology and for the near future, we still can't build a real Quantum computer that can even begin to tackle this problem, let alone solve it.

i think you are not understanding, my english was clear enough in the last post you quoted, quantum computer can break any 128 key, it has been said many times, there is no question here

now, public key are 128 bit, instead private key are 256, so the first can be brute forced by any quantum computer, and if you have that key you could retrieve the private key, but this only if the targeted public key is send when you spend a transaction

here a link http://bitcoin.stackexchange.com/questions/6062/what-effects-would-a-scalable-quantum-computer-have-on-bitcoin

there are many other confirming this

Thank you to this link,  thanks to it I have found this thread (of Come-from-Beyond) : https://bitcointalk.org/index.php?topic=153302.0


Don't want to open the link, here the post:

As we all know elliptic curve cryptography is vulnerable to a quantum computer. For a conventional computer difficulty of breaking 256-bit key equals 256/2=128 bits. For a quantum computer it's just sqrt(256)=16 bits.
Bitcoin address is a hashed public key of 256-bit EC. Hashes are resistant to quantum algos, so while someone keeps his public key unknown it's OK. But when he wants to transfer his money he must reveal the key.
Let's assume that an attacker with a quantum computer monitors all transactions. The attacker can pick any key while a transaction awaits to be included into a block. Now imagine that miners choose transactions with higher fees. The attacker can issue other transaction (when he picks the private key) that transfer coins to his address and set a higher fee. Or he could switch his mining rig on and try to find a block himself. With 0.1% of all hashpower he needs only 5 days to solve a block with 50% chance.

Seems Bitcoin is NOT safe. Or am I wrong?

We can assume everything because I didn't still see a valid and functionally quantum computer.

[Sarthak]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

[redsn0w]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

[RodeoX]

I think yes. But at that point bitcoin may be the least of our worries.

[Sarthak]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

Yes! Innovation never stops! There are already better altcoins than Bitcoin out there! One of them will replace Bitcon in the near future! I see the future in altcoins Bitcoin was not the first digital currency and it won't be the last

[sickpig]

Quantum computing studies theoretical computation systems (quantum computers) that make direct use of quantum-mechanical phenomena, such as superposition and entanglement, to perform operations on data.
Large-scale quantum computers will be able to solve certain problems much more quickly than any classical computers that use even the best currently known algorithms.
In theory this kind of computing power will be unbelievably powerful and be able to achieve much greater "solving power" which could crack algorithm behind bitcoin (commonly referred as: public key cryptography).

For more information visit: http://en.wikipedia.org/wiki/Quantum_computing

Bitcoin is designed to last for over a 100 years. Obviously we don't have this kind of computers yet.
But we will be, maybe in 10 maybe in 20 years, but definitely sooner that we may think - and then, at that time bitcoin may be world currency...
So do you think quantum computers would break Bitcoin's security?

If you're interested in such a matter just have a look to this site: http://pqcrypto.org/

Here's the one-minute introduction: "Imagine that it's fifteen years from now. Somebody announces that he's built a large quantum computer. RSA is dead. DSA is dead. Elliptic curves, hyperelliptic curves, class groups, whatever, dead, dead, dead. So users are going to run around screaming and say 'Oh my God, what do we do?' Well, we still have secret-key cryptography, and we still have some public-key systems. There's hash trees. There's NTRU. There's McEliece. There's multivariate-quadratic systems.

Fascinating to say the least.

[LiteCoinGuy]

Quantum computers could "theoretically" effect a number of industries including the banking sector. So bitcoins will be the least of our worries.

I'm really not worried so much, mainly because the same computing power could also be used to aid in creating stronger cryptology as well. There are a number of other countries including China, Russia and India, ect. who are not just sitting around waiting for their secure systems to be hacked by quantum computing.

There will be pluses and minuses on both sides of the table as we learn more about this technology and overall all we'll learn how to use it to make our encryption schemes even more secure.

[redsn0w]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

Yes! Innovation never stops! There are already better altcoins than Bitcoin out there! One of them will replace Bitcon in the near future! I see the future in altcoins Bitcoin was not the first digital currency and it won't be the last

You are rigtht, innovation will never stop but I think bitcoin will exist for another 50-100 years. Do you remember when internet was 'released' to all the people.... and we are still using it (waiting for a new protocol, better than this one).

[Sarthak]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

Yes! Innovation never stops! There are already better altcoins than Bitcoin out there! One of them will replace Bitcon in the near future! I see the future in altcoins Bitcoin was not the first digital currency and it won't be the last

You are rigtht, innovation will never stop but I think bitcoin will exist for another 50-100 years. Do you remember when internet was 'released' to all the people.... and we are still using it (waiting for a new protocol, better than this one).

Maybe not! 10-15 years and it will die.. Perhaps, it may die soon.. But since its already adopted by many people, it will take a while to die forever

[redsn0w]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

Yes! Innovation never stops! There are already better altcoins than Bitcoin out there! One of them will replace Bitcon in the near future! I see the future in altcoins Bitcoin was not the first digital currency and it won't be the last

You are rigtht, innovation will never stop but I think bitcoin will exist for another 50-100 years. Do you remember when internet was 'released' to all the people.... and we are still using it (waiting for a new protocol, better than this one).

Maybe not! 10-15 years and it will die.. Perhaps, it may die soon.. But since its already adopted by many people, it will take a while to die forever

Nah only  10-15 years. I think it will exist for the next (at least) 50 years, we should remember it was created only in the 2009 and I think it will be used for a long time.

[lucasjkr]

Yes. If quantum computers become a reality (and there is serious question about that) then they would upend everything, including Bitcoin. Is that something to seriously worry about today? No.

[Sarthak]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

Yes! Innovation never stops! There are already better altcoins than Bitcoin out there! One of them will replace Bitcon in the near future! I see the future in altcoins Bitcoin was not the first digital currency and it won't be the last

You are rigtht, innovation will never stop but I think bitcoin will exist for another 50-100 years. Do you remember when internet was 'released' to all the people.... and we are still using it (waiting for a new protocol, better than this one).

Maybe not! 10-15 years and it will die.. Perhaps, it may die soon.. But since its already adopted by many people, it will take a while to die forever

Nah only  10-15 years. I think it will exist for the next (at least) 50 years, we should remember it was created only in the 2009 and I think it will be used for a long time.

Its future anyways! Noone exactly knows what's happening in the future.. Hey redsn0w, the best option is to sit and watch (We can bet if you're interested )
What do you think?

[BADecker]

Yes and no.

Bitcoin encryption can easily be made countless times more difficult.

By the time quantum computers are capable of breaking the blockchain, Bitcoin encryption will have been made so extremely strong that regular computers will have a hard time just working with the encryption, but even quantum computers won't be able to break it.

Then, people will start getting quantum computers in their homes, and this will make Bitcoin encryption stronger than ever.

All this is a loooooong ways off. Lots of other things will have a much better chance of collapsing Bitdoin before quantum computers are ready to do it.

[lucasjkr]

SHA256 will never be cracked during our lifetime and beyond, this is a non issue. Efforts should be put instead in what to do with the blocksize limit.

They probably said that about MD5 and SHA1. Careful.

[olcaytu2005]

 Guys why are you wonder about that ? Don't worry coz if quantum computers to be invented and they try to hack blockchain, then blockchain will use quantum algorithm and will be secure

as i said dont worry. If technology improve at the same time blockchain will be improved itself.

[redsn0w]

I don't think we will be using Bitcoin Technology until the quantum computer era starts... Just my personal opinion!

Why? Do you think it will exist/created a new concept better than the actual bitcoin? I think the blockchain will exist for ever, it is an invention like internet and all we know it is extremely difficult to replace the internet protocol.

Yes! Innovation never stops! There are already better altcoins than Bitcoin out there! One of them will replace Bitcon in the near future! I see the future in altcoins Bitcoin was not the first digital currency and it won't be the last

You are rigtht, innovation will never stop but I think bitcoin will exist for another 50-100 years. Do you remember when internet was 'released' to all the people.... and we are still using it (waiting for a new protocol, better than this one).

Maybe not! 10-15 years and it will die.. Perhaps, it may die soon.. But since its already adopted by many people, it will take a while to die forever

Nah only  10-15 years. I think it will exist for the next (at least) 50 years, we should remember it was created only in the 2009 and I think it will be used for a long time.

Its future anyways! Noone exactly knows what's happening in the future.. Hey redsn0w, the best option is to sit and watch ;D (We can bet if you're interested )
What do you think?

Yes obviously, we can't do nothing only sit and watch what will happen after the first quantum computer will be created and it will be fully functional. For the question of the bet, nah I don't like these type of thing and I can't imagine how we can bet (it's 10-15 years  ).

SHA256 will never be cracked during our lifetime and beyond, this is a non issue. Efforts should be put instead in what to do with the blocksize limit.

They probably said that about MD5 and SHA1. Careful.

Here we are only speculate about an hypothetical quantum, so it may happen everything.