> Are you saying that if/when quantum computing comes around, existing encryption systems would be suddenly ineffective?
Yes, but it's a big "if". There are many obstacles that stand in the way of quantum computing on a large scale, in fact some believe it will never be possible to maintain the delicate conditions required to perform quantum computation on a large scale.
The reason quantum computing could outperform conventional computation is because a quantum computer would, in a manner of speaking, process all possible problem statements at once, in parallel, and arrive at the best solution just as though only one problem statement had been processed. I know that may be difficult to imagine, but so is quantum. About quantum theory, John Wheeler said, "If you are not completely confused by quantum mechanics, you do not understand it."
Suffice it to say that quantum computing on a scale sufficient to pose a threat to public-key cryptosystems is not just around the corner.
I think that's the wrong attitude to take. If you look at the mathematics there is really nothing so weird or magical about quantum mechanics or using it to perform factorization; you just take a set of qbits initially in an equal superposition of all possible factors, manipulate them through quantum operations such that the amplitudes of all the factors that don't divide the number go to zero, and then measure the state to force a collapse/entangle yourself with it, and the number you measure will necessarily be a factor. QM in general is really pretty simple and even obvious if you ignore the silly mythology and just follow the math.
As for the specifics, I believe we have working 4-qbit quantum computers, and shor's algorithm has been successfully applied to calculate that 15=3x5. But current approaches do indeed seem unlikely to scale up to 1024 qbits.
> If you look at the mathematics there is really nothing so weird or magical about quantum mechanics or using it to perform factorization ...
Yes, if you examine the mathematics that's true, but if you examine the physics it's not true. The problem doesn't lie with algorithm design, the problem lies with putting them into practice in actual physical computers.
> QM in general is really pretty simple and even obvious if you ignore the silly mythology and just follow the math.
On the contrary, not at all simple if one must try create an actual physical realization.
This is not to suggest that the problems won't be overcome, only that they're more formidable than describing how easy it is in principle.
Comments
> Are you saying that if/when quantum computing comes around, existing encryption systems would be suddenly ineffective?
Yes, but it's a big "if". There are many obstacles that stand in the way of quantum computing on a large scale, in fact some believe it will never be possible to maintain the delicate conditions required to perform quantum computation on a large scale.
The reason quantum computing could outperform conventional computation is because a quantum computer would, in a manner of speaking, process all possible problem statements at once, in parallel, and arrive at the best solution just as though only one problem statement had been processed. I know that may be difficult to imagine, but so is quantum. About quantum theory, John Wheeler said, "If you are not completely confused by quantum mechanics, you do not understand it."
Suffice it to say that quantum computing on a scale sufficient to pose a threat to public-key cryptosystems is not just around the corner.
I think that's the wrong attitude to take. If you look at the mathematics there is really nothing so weird or magical about quantum mechanics or using it to perform factorization; you just take a set of qbits initially in an equal superposition of all possible factors, manipulate them through quantum operations such that the amplitudes of all the factors that don't divide the number go to zero, and then measure the state to force a collapse/entangle yourself with it, and the number you measure will necessarily be a factor. QM in general is really pretty simple and even obvious if you ignore the silly mythology and just follow the math.
As for the specifics, I believe we have working 4-qbit quantum computers, and shor's algorithm has been successfully applied to calculate that 15=3x5. But current approaches do indeed seem unlikely to scale up to 1024 qbits.
> If you look at the mathematics there is really nothing so weird or magical about quantum mechanics or using it to perform factorization ...
Yes, if you examine the mathematics that's true, but if you examine the physics it's not true. The problem doesn't lie with algorithm design, the problem lies with putting them into practice in actual physical computers.
> QM in general is really pretty simple and even obvious if you ignore the silly mythology and just follow the math.
On the contrary, not at all simple if one must try create an actual physical realization.
This is not to suggest that the problems won't be overcome, only that they're more formidable than describing how easy it is in principle.