Bitcoin Forum

How much of a threat is quantum computing at the moment.

All it would take is one entity to achieve significant quantum computing power (NSA in UTAH!?), and all of the sudden we have a real problem. Right?

Info and thoughts welcome

Oh we'll have a problem all right, but not just with Bitcoin. Encryption methods used by every bank will also be at risk at that point.

Strictly speaking, at the moment, quantum computing isn't a threat (or of use) to anyone since it's still nothing more than a science experiment.

So it wouldn't be far fetched to assume that there is some type of race towards quantum computing in the higher levels of security administrations. It would be like a universal key to everything.

Yes... Bitcoin would be the least of anyones worries if a general purpose, stable QC were to be made available.  It would basically destroy the entire security industry in one grand stroke, and everything, everywhere would be insecure.  Compared to that, Bitcoin wouldn't even be a blip on the radar.

So yes it is an issue (a big one), but no it isnt time pressing as far as we know.
Maybe a quantum encryption method will be created anyway, and we would just use that.

If the bitcoin project has any ambition, this is really not a good answer.

The point is, it's not a threat that needs attention at the moment.  If it were, you can be other industries would already be scrambling to find solutions.  As far as I know, right now, they've been able to make a QC do several bits of computing at a really slow rate for about 2 minutes max before the computer becomes unstable and collapses.

Your 8088 has nothing to worry about at the moment, let alone modern equipment.

On the flip side, isn't quantum cryptography being developed/in use?  I think it has been developed and cracked already, but I believe the quantum cryptography fundamentals are solid, just the implementation that needs to be corrected (I am by no means knowledgeable about the subject, just trying to recall some things I read awhile back)

"quantum cryptography" right now is only "quantum communications" and less "quantum computing". they use quantum effects like entanglement to safe transfer info from A to B.

Quantum cromputing has an advantage against the current implementation of public-private key encryption standards, RSA I think. If those computers ever got close to being able to crack those encryptions, people would just start using keys with more bits or come up with a new public-private key methodology that wasn't as vulnerable. Bitcoin would update and move on. That's what I understand, at least.

Yes. this kind of technological quantum leaps are  always serious threats.

Imho.

Hm, I dont think using bigger key will help. If anyone gets a quantum stable turing machine (and thats about a finite number of q computer elements, less than 100), it can be programmed to run any algorithm. It wont help to have a bigger key since it will be able to brute force any regular encryption algorithm in same amount of time.

Hmm.  The other hundred threads on this same topic all came to the conclusion that QC wasn't a problem for the next decade or more, and that we'd have plenty of time to adapt as technology improves.

I'm going to watch this thread, just in case it turns out differently from the others.

this question is kinda like the Y2K bug

"EVERYTHING WILL FALL APART!"

come on!

lol

Just as the stupidity of humanity never fails to amaze (viz pirate pyramid) so too for human ingenuity.  Any technological advance can be countered given sufficient motivation.

There are encryption schemes that are resistant to being broken by quantum computers.

http://en.wikipedia.org/wiki/Unbalanced_Oil_and_Vinegar

IMHO quantum computing is less of an issue to bitcoin than time travel.

Is the real danger from Scott Bakula going back in time to buy up all the BTC when it was <$1/BTC??  :D

rofl, yes, everyone will crash into each other on Jan 3rd 2009.

Back in 2009 Shor's algorithm had been used by a quantum computer to factorise the number 15. Anyone know what the most recent record is?

https://bitcointalk.org/index.php?topic=3008.0 an enlightening thread on this topic

Besides unbalanced oil & vinegar, NTRU exists today and has an open source implementation: http://en.wikipedia.org/wiki/NTRU
There are also one-time Lamport signatures + merkle trees that allow for more than one sig use: http://en.wikipedia.org/wiki/Lamport_signature

Both of these have serious downsides compared to ECDSA though, namely a lot more data is required for public keys and signatures. But they are quantum computer resistant.

15!  But this time with electrons, and this time it was really truly Quantum^TM, for sure.

Also, according to Wikipedia, the first factoring was done in 2001.  It may not have actually been a quantum event since entanglement wasn't observed, but I'd think that teaching an NMR machine to factor integers would be a bigger accomplishment!  After all, everyone "knows" that quantum computing is coming, but getting Shor's to work in a non-quantum computer would change the world.