Well in theory a true general purpose quantum computer with a massive number of quibits (say 30,000+) would be very useful for breaking all types of public key cryptographic including ECDSA used by Bitcoin.

The good news is like you said it is one of those things (economical fusion power being another) which has been "so close" for decades now.  The other thing is that DWAVE computer isn't a general purpose quantum computer so while the threat exists it is still academical at this point.

Schroedinger's Bitcoin?

just like cold fusion.

More likely to help improve their search and thus their targeted advertising through learning from your past searches etc. Google is becoming self aware in other words.

This also has applications for their cars that can drive themselves etc.

what if we actually did get sucked into an alternate universe but we didn't realize, and the people at power now are the ones behind the LHC and they trapped us in a matrix like scheme, and satoshi is also one of the guys from the original universe, but he has gone rogue.

and now they're trying to make really powerful agents to stop the bitcoin threath.

Bitcoin isn't doomed.

Quantum computers have the potential to be hashing monsters in the near term should anyone come up with a Quantum Miner to crunch SHA256 algos, but the algorithm that protects our keys is Elliptic Curve cryptography based which is many orders or magnitude higher.

That's not to say it's impossible for Quantum Computers to catch up.

But even if this was the case, the moment any real risk came up we always have the option of having Bitcoin's equivalent of a constitutional amendment, a hard fork. Provided it was properly managed, scheduled and agreed on there is no reason a stronger encryption function couldn't be implemented onto the blockchain.

Think about the transition from IPV4 to IPV6 - it didn't stop the old addresses from working, it just added the extra functionality on top and anyone who wanted to take advantage of the new functionality simply opts into it.

Much the same for Bitcoin, there just has to be consensus.

So quit worrying - Bitcoin is community run and can evolve to handle anything that gets thrown at it.  

Sorry , but is that a true and working quantum computer?

Yes it was able to factor 21 into 7 & 3.  One capable of breaking a 256 bit ECDSA key would need to be 4000x to 5000x larger and there has been essentially no progress in building even modestly larger QC (i.e. one that could break an already obsolete 32 bit key in a reasonable amount of time) in the last decade.

Excellent! At least I know that in another timeline I did not don a pink tutu in Las Vegas, albeit I pity them souls that were forced to listen to the Bitcoin for Goats presentation.

~TMIBTCITW

PS: This thread should be finished now.

That's a bit scary ! :/