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> My understanding is that none of D-wave's systems for instance are anywhere close to implementing Shor, and I treat that as my "are we there yet" test. Do yo

> My understanding is that none of D-wave's systems for instance are anywhere close to implementing Shor, and I treat that as my "are we there yet" test. Do you care about the algorithm, or the result? Currently we can factor 11-bit semiprimes fairly reliably, and our hardware is capable of running 16-bit problems. But no, it's not Shor's algorithm. It's conceptually much simpler: implement a multiplication circuit, clamp the output, anneal to find the inputs. Despite not being Shor's algorithm, we've yet to see a competitor demonstrate anything close on the factoring problem. There's a strange thing in quantum computing happening right now. Certain people believe that there's only one kind of quantum computing, because it's got a provable speedup under yet-unobtainable assumptions. Adiabatic quantum computing, under a similarly unobtainable set of assumptions, can run the same algorithms, polynomially equivalent in time and space. But gate-model gets all the hype. And speaking of hype, 2017 just called. https://spectrum.ieee.org/computing/hardware/google-plans-to-demonstrate-the-supremacy-of-quantum-computing https://spectrum.ieee.org/computing/hardware/google-plans-to...

xiphias2 7y ago
I mostly care about the available time for Bitcoin to switch to quantum secure cryptography. It’s scary that people wouldn’t accept a 10x fee increase which would be necessary for the switch.
- postalrat 7y ago
  It's already too late. Even if they switched now it wouldn't save all the coins stored in older addresses. They need to choose between removing a large part of the coins from the blockchain or accepting that those coins will be taken by whoever has the technology first. Both options are bad for bitcoin.
  - xiphias2 7y ago
    It'a not that bad, it's easy to add a new digital signature to Bitcoin (the hard part is developing one that's accepted by the community). Most of the money can be consolidated to less UTXOs. The problem will still be that we have no idea when the current signatures get unsecure.
RagingCactus 7y ago
Are there any resources you can recommend to understand D-wave's quantum computing a bit better? I took a very basic course about gate-model quantum computing at my university. The (mathematics) professor would have loved to be able to explain adiabatic quantum computing on a basic level, but was unable to find entry-level material to really understand how it works or what problems it can solve.

xiphias2 7y ago

I mostly care about the available time for Bitcoin to switch to quantum secure cryptography. It’s scary that people wouldn’t accept a 10x fee increase which would be necessary for the switch.

postalrat 7y ago
It's already too late. Even if they switched now it wouldn't save all the coins stored in older addresses. They need to choose between removing a large part of the coins from the blockchain or accepting that those coins will be taken by whoever has the technology first. Both options are bad for bitcoin.
- xiphias2 7y ago
  It'a not that bad, it's easy to add a new digital signature to Bitcoin (the hard part is developing one that's accepted by the community). Most of the money can be consolidated to less UTXOs. The problem will still be that we have no idea when the current signatures get unsecure.

RagingCactus 7y ago

Are there any resources you can recommend to understand D-wave's quantum computing a bit better? I took a very basic course about gate-model quantum computing at my university. The (mathematics) professor would have loved to be able to explain adiabatic quantum computing on a basic level, but was unable to find entry-level material to really understand how it works or what problems it can solve.