Bitcoin Forum

Bitcoin has been a great social experiment thus far, but there have been recent developments in quantum computing. Speculatively speaking, what effect might this have on bitcoin and the next generation of cryptocurrencies?

http://bits.blogs.nytimes.com/2014/03/24/quantum-computing-research-may-back-controversial-company/?_php=true&_type=blogs&_r=0

"While the controversy has gone on for years, it may reach an end within a year or two. Mr. Williams said that in April, D-Wave will be conducting experiments with a machine managing over 1,000 qubits, about twice the number currently inside its best machine.

A 2,000-qubit machine is scheduled for the end of the year, and will be ready for experiments within a few months after that. If D-Wave can rapidly solve the kind of large problems a machine like that is expected to, that would perhaps be the most persuasive evidence possible that we have entered a new computing era."

if you can decrypt with quantum computer .. what's the problem about encrypt with quantum computer ???

Bitcoin uses SHA256, the whole world uses this algo. So there will be no headline tomorrow "mega quantum computer solves sha256 hash in 3 hours". It more like "Instead of 2^78 years you would only need 2^77 years. In 10 years down to 2^67 years."
So there would be enough time to chance to different algorithms.

This topic has come up many times before.

I believe ECDSA is considered weak against a full blown quantum computer (which is still a ways away) but that other algorithms that are believed to be quantum resistant are already developed. Bitcoin would need a hard fork and switch.

SHA256 hashing should still be fine. A quantum computer can not beat SHA256 but would exponentially increase the difficulty. So ASICs would become paper weights and the quantum computer owners billionaires. Personally I find this to be acceptable, the scientists who finally get a working quantum computer deserve some rewards.

If you haven't used your address and only have inputs but no outputs then you're safe, even quantum computers cannot steal your coins then.

Fuck your quantum computers. Fuck them right up your ass.

I like quantum soup ...

Symphony of Science - the Quantum World!
https://www.youtube.com/watch?v=DZGINaRUEkU

I had to laugh. I must be drunk^^

d-wave is a boondoggle.  a cracking good (pun) qc might come out one day, but it won't be adiabatic.

If quantum computing is able to crack SHA256 in minutes/hours, the primary target will not be bitcoin. It's lot easier to access banks, security and insurance companies, for instant rewards.

A real quantum computer exists outside of time and space. The real threat will be Daleks.

not for "instant rewards" but show then that there is something bigger than they are ...

banks depends upon cryptology ...so don't mess with us ...

They can't run Shor's algorithm. neither the prime one nor the modified version for elliptic curves.

The gamers will be livid with us as we would go on a buying frenzie to get all the quantaum comps to mine da coins.

This is misleading and wrong.
Any public key that hashes to the same address can spend from that address if the public key was not revealed.
So you can also brute force addresses that have only received coins.
The question is can you find efficient algorithms for quantum computers to solve these problems in a reasonable amount of time.