[2016-11-21]Will Quantum Computers Be the End of Bitcoin?

[WishICanTurnBackTime]

Will Quantum Computers Be the End of Bitcoin?

Quantum computers, for all of their press, will not be used in everyday applications such as running word processors or playing games. Rather,
they will help with large data processing tasks and problem solving. However, while most individuals on this planet only have positive intentions for such inventions, there are others who have malicious intentions.
Quantum computers have an incredible ability to perform multiple calculations simultaneously, unlike conventional computers. For example, modern computers could never brute force hack a 256-bit key by going through every combination whereas a quantum computer could achieve this with ease.
To put the speed difference into perspective, Google's D-Wave 2X quantum computer can solve algorithms 100,000,000 faster than modern computing devices. This means that brute force attacks on security protocols will suddenly become viable which will cause serious issues with global finance, computing, and information as a whole. So it comes as no surprise that Bitcoin is at serious risk from quantum computers becoming commonplace.

http://www.allaboutcircuits.com/news/will-quantum-computers-be-the-end-of-bitcoin/

[DooMAD]

Typical click-bait headline.  If it's the end of Bitcoin, it's also the end of fiat.  The entire legacy finance sector relies on encryption too.  I almost didn't bother reading the article as a result of the title, because it's just getting tiresome now, but read it to see if they got around to acknowledging the fact that everything is vulnerable to something that can crack encryption.  Got there in the end.   

I'm also inclined to speculate that Bitcoin will be faster to react to the problem than the banks will.  We're the ones on the bleeding edge here.  Can't say I'm all that concerned.

[mindrust]

This has been brought many times before. I was also worried about this but i see the experts in this forum say the otherwise. So, the answer is no. Quantum Computing can't harm or hack bitcoin system.

[Karartma1]

This has been brought many times before. I was also worried about this but i see the experts in this forum say the otherwise. So, the answer is no. Quantum Computing can't harm or hack bitcoin system.

https://bitcointalk.org/index.php?topic=1645557.msg16579832#msg16579832

https://bitcointalk.org/index.php?topic=1647214.0

I post the above as a reference for those who are interested in discover a bit more. And by the way don't be afraid of quantum computing

[tyz]

Each year a new article about the danger of Quantum Computer for Bitcoin.

I felt this familiar and I searched my old threads and here we are 
https://bitcointalk.org/index.php?topic=1202042.0

[Priam]

Well, that is frightening me a bit, but there's bigger than Bitcoin to attack, as pointed above. Also, I think that some solutions will be found if it reveals to be a real threat.

[odolvlobo]

This has been brought many times before. I was also worried about this but i see the experts in this forum say the otherwise. So, the answer is no. Quantum Computing can't harm or hack bitcoin system.

Anyone that says that "quantum computing can't harm or hack bitcoin system" is obviously not an expert.

The danger is real. While quantum computing is still in an experimental state now, the companies developing quantum computers expect the computational power to double every year. SHA-256 and ECC are expected to be broken in as soon as 10 years, and certainly less than 20 years.

Each year a new article about the danger of Quantum Computer for Bitcoin.

I felt this familiar and I searched my old threads and here we are 
https://bitcointalk.org/index.php?topic=1202042.0

These articles keep coming up because the danger is real and looming. Pretending that it doesn't exist won't make it go away.

If it's the end of Bitcoin, it's also the end of fiat.  The entire legacy finance sector relies on encryption too. ...

That's like writing, "I don't care if I die because everyone else is going to die, too."

[DooMAD]

If it's the end of Bitcoin, it's also the end of fiat.  The entire legacy finance sector relies on encryption too. ...

That's like writing, "I don't care if I die because everyone else is going to die, too."

Not when you're implying later in the same post that someone is bound to come up with a fix due to what's at stake.  No one's denying it's a serious risk if we let it happen, but I don't think we're foolish enough to let things reach that point.  As soon as the notion became a possibility that something could crack encryption, keener minds than mine were already thinking up potential solutions.  If you know what's coming, it's easier to defend against.  It wouldn't surprise me if it was someone (or a group of someones) here in the crypto community who solves it.  I'm fairly confident anti-quantum algorithms will probably be a reality before quantum itself becomes an issue.

And again, it was mostly just pointing out stupid clickbait headline is stupid.

[kryptqnick]

I heard the news that quantum computer is sort of already created but it is still not that powerful. I don't believe scientists can invent such a thing. And even if they do... We can see here http://bitcoin.stackexchange.com/questions/2847/how-long-would-it-take-a-large-computer-to-crack-a-private-key that it would take 0.65 billion billion years for our computers to do so. If quantum computer is 100 000 faster then instead of 6.5*10^17 years it would take 6.5*10^12 which doesn't make much difference.

[panju1]

I heard the news that quantum computer is sort of already created but it is still not that powerful. I don't believe scientists can invent such a thing. And even if they do... We can see here http://bitcoin.stackexchange.com/questions/2847/how-long-would-it-take-a-large-computer-to-crack-a-private-key that it would take 0.65 billion billion years for our computers to do so. If quantum computer is 100 000 faster then instead of 6.5*10^17 years it would take 6.5*10^12 which doesn't make much difference.

Even if quantum computers are developed to crack asymmetric cryptographic problems in reasonable amounts of time, we can move to an quantum-computer resistant algorithm to secure Bitcoin.
An earlier article explaining the same..

https://cointelegraph.com/news/the-arrival-of-quantum-computing-threat-to-bitcoin

[odolvlobo]

I heard the news that quantum computer is sort of already created but it is still not that powerful. I don't believe scientists can invent such a thing. And even if they do... We can see here http://bitcoin.stackexchange.com/questions/2847/how-long-would-it-take-a-large-computer-to-crack-a-private-key that it would take 0.65 billion billion years for our computers to do so. If quantum computer is 100 000 faster then instead of 6.5*10^17 years it would take 6.5*10^12 which doesn't make much difference.

Unfortunately, it isn't that easy to dismiss. There are two factors: the computational speed and the algorithm.

A quantum computer using a simple brute force algorithm like what might be done on current computers indeed would not be a problem. However, quantum computers are especially suited for using a different algorithm that reduces the computation time by a huge factor.

An analogy

The time to search an unsorted array is described as Θ(n), which means the average number of operations is proportional to the number of items in the array. In contrast, the time to search a sorted array is Θ(log n).

Let's compare times assuming that an operation takes 1 ns (¹/_1000000000 second).

Count	Unsorted Ops	Sorted Ops	Time Comparison
10	10	3	10 ns vs. 3 ns
1000	1000	10	1000 ns vs. 10 ns
1 million	1 million	20	1000000 ns vs. 20 ns
1012	1012	40	1000 second vs. 0.000000040 seconds
2128	2128	128	1020 centuries vs. 0.000000128 seconds

The algorithm makes all the difference in the world. Please note that the times are not actual times, and there is quite a bit of hand waving.

In the end, as panju1 and DooMAD noted, a solution is to switch to a "quantum-resistant" cryptography. However, quantum-resistant cryptography is still being developed, and the danger is that quantum computers will be able to break current cryptography (including Bitcoin) before quantum-resistant cryptography can be developed.