512-qubit Quantum Computer acquired, is bitcoin doomed?

[bluemeanie1]

D-Wave also has a fairly good introductory tutorial on Quantum Computing for programmers:

http://www.dwavesys.com/en/dev-tutorial-intro.html

[Operatr]

Quantum cryptography. Problem solved

[Lauda]

I wouldn't worry if it presented a risk, developers could patch it up with something more resistant to quantum computers.

[tacotime]

The search space for private keys via ECDSA is reduced from 2^128 to 2^64 using Shor's algorithm if I recall correctly, so not really.

[RoadToHell]

I want to pre-order USB powered Quavalon mining rig that do 1PH/s 

Is Butterfly Labs taking preorders for those yet?

No, but I am.  Send your share bids to the address in my profile.

Due to the Heisenberg uncertainty principle, the more we check on the delivery date the harder it will be to lock it down.  Right now delivery will be at some point in the future and I don't want to risk anything by trying to be more precise.

[etotheipi]

Unless D-Wave has changed their direction in the last 5 years (the last time I checked in with their progress), nothing they are doing actually constitutes a "real quantum computer".  When I say "real," I mean one of those quantum computers that actually leverages quantum interference to solve problems, which could be used to break not just Bitcoin cryptography, but all the cryptography on which the internet is based.  If this was a real problem, you can be sure that alarm bells would be ringing around the world, and for much more than just Bitcoin. 

Real quantum computers aren't just faster -- they solve problems differently.  Shor's algorithm takes integer factorization from O(e^cuberoot(N)) on a classical computer to O(N²) on a quantum computer.  This isn't just faster -- this makes a whole class of essentially-unsolvable problems, solvable (including the discrete logarithm problem on which Bitcoin crypto is based). 

Yes, you can get a speedup on pure-guessing problems using Grover's algorithm -- from O(2^N) to O(2^N/2).  That's a unique capability that QCs can exploit, but the least interesting in terms of breaking cryptosystems.  Most crypto systems use key sizes big enough that even if you halved the keysize, it would still be secure.  And the defense is to just double your keysizes, once, and the problem goes away.  But not with Shor's algorithm -- the whole class of problems is compromised.

D-Wave has always been a joke in the world of QCs.  What they are doing is cool, and they may be developing technology that is somewhat related to QCs, but they shouldn't be using the phrase "Quantum Computing" in their product name, because that terms is reserved for a whole new class of computing systems, not classical computers that use quantum bits to do things classically faster.

[bluemeanie1]

Unless D-Wave has changed their direction in the last 5 years (the last time I checked in with their progress), nothing they are doing actually constitutes a "real quantum computer".  When I say "real," I mean one of those quantum computers that actually leverages quantum interference to solve problems, which could be used to break not just Bitcoin cryptography, but all the cryptography on which the internet is based.  If this was a real problem, you can be sure that alarm bells would be ringing around the world, and for much more than just Bitcoin.  

Real quantum computers aren't just faster -- they solve problems differently.  Shor's algorithm takes integer factorization from O(e^cuberoot(N)) on a classical computer to O(N²) on a quantum computer.  This isn't just faster -- this makes a whole class of essentially-unsolvable problems, solvable (including the discrete logarithm problem on which Bitcoin crypto is based).  

Yes, you can get a speedup on pure-guessing problems using Grover's algorithm -- from O(2^N) to O(2^N/2).  That's a unique capability that QCs can exploit, but the least interesting in terms of breaking cryptosystems.  Most crypto systems use key sizes big enough that even if you halved the keysize, it would still be secure.  And the defense is to just double your keysizes, once, and the problem goes away.  But not with Shor's algorithm -- the whole class of problems is compromised.

D-Wave has always been a joke in the world of QCs.  What they are doing is cool, and they may be developing technology that is somewhat related to QCs, but they shouldn't be using the phrase "Quantum Computing" in their product name, because that terms is reserved for a whole new class of computing systems, not classical computers that use quantum bits to do things classically faster.

etotheipi, an article I just ran into that reflects your comments here : http://www.scottaaronson.com/blog/?p=1400

It's true that when you cross over into the commercial arena, you typically encounter disjoints between promises and reality.  Whenever you get enough public interest in some scientific idea, eg. Quantum Computing, someone will claim to be delivering it despite it being impossible.

There are projects being advertised right here in this forum, that claim even to be Open Source, that don't even come close to living up to the claims made about it.

because once one slices through all the layers of ugh—the rigged comparisons, the “dramatic announcements” that mean nothing, the lazy journalists cherry-picking what they want to hear and ignoring the inconvenient bits

sounds a lot like a project I know...

[jackjack]

Quantum computing is possible

[defaced]

dooomed, dump all your btc now

:trlf:

[Lauda]

dooomed, dump all your btc now

:trlf:

Dump to me @1$ each, don't worry it's a good investment the price of $ will rise by 1% psst! 

[jackjack]

I'd take them at $20 each
Beware they may contain viruses too

[psystyle]

No.

Yes.

maybe 

[QuestionAuthority]

Yes, Bitcoin is doomed so give me all your coins and run away like a little school girl that had her first period in a white skirt at the school cafeteria.

[freedomno1]

Yes, Bitcoin is doomed so give me all your coins and run away like a little school girl that had her first period in a white skirt at the school cafeteria.

So detailed  

Edits In: Question Authority wants to be a little girl
(Moot)

[Boussac]

No.

Yes.

it is both doomed and not doomed at the same time.

+1
Best geek joke of the day.
Then again quantum computing lends itself to easy geek jokes..

[fenican]

Nice quote from Umesh Vazirani, a professor at UC Berkeley on the D-Wave hardware:

"even if it turns out to be a true quantum computer, and even if it can be scaled to thousands of qubits, would likely not be more powerful than a cell phone"

Great skepticism out there as to whether D-Wave is doing anything truly Quantum or, rather, is just building dedicated hardware to create approximate, not exact (i.e. useless for Crypto) solutions to complex problems.

Nothing D-Wave is doing will have any effect of the strength of cryptography they are definitely NOT building general purpose quantum computers or quantum computers that can break high grade cryptography algorithms.

[Cyrus17]

No.

[kjj]

By now, there are so many threads on quantum computers that to have missed them all is simply impossible.  Just typing the word "quantum" into the search box gives 28 pages of results.

We need a time out corner.

[StarfishPrime]

Quantum computing = the "hydrogen-powered car" of computer research.

Always "just around the corner", lots of hype and FUD, but never quite moving beyond a technical curiosity. The only way quantum computing could generate more baseless hype is if someone ports the litecoin client to run on a D-Wave box 

Quantum computing will be big for many things, but cracking bitcoin keys - or running Windows 8 -  are probably not two of them.

[Lauda]

Quantum computing = the "hydrogen-powered car" of computer research.

Always "just around the corner", lots of hype and FUD, but never quite moving beyond a technical curiosity. The only way quantum computing could generate more baseless hype is if someone ports the litecoin client to run on a D-Wave box 

Quantum computing will be big for many things, but cracking bitcoin keys - or running Windows 8 -  are probably not two of them.

last part +1