Thread: Quantum Computing - The end of modern day encryption/hashing?

Just curious, but once Quantum Computing is usable and could calculate infinite calculations instantly.

Wouldn't any hash/encryption algorithm methods that we know of today be instantly pretty much plain text.

They could just bruteforce all possibilites of input.

Originally Posted by ScienceNoob

Just curious, but once Quantum Computing is usable and could calculate infinite calculations instantly.

Wouldn't any hash/encryption algorithm methods that we know of today be instantly pretty much plain text.

They could just bruteforce all possibilites of input.

The first sentence describes an impossibility. Quantum computing may be fast, but it can carry out only a finite number of calculations in a finite length (non-zero) amount of time.

Originally Posted by mathman

Originally Posted by ScienceNoob

Just curious, but once Quantum Computing is usable and could calculate infinite calculations instantly.

Wouldn't any hash/encryption algorithm methods that we know of today be instantly pretty much plain text.

They could just bruteforce all possibilites of input.

The first sentence describes an impossibility. Quantum computing may be fast, but it can carry out only a finite number of calculations in a finite length (non-zero) amount of time.

Ahh I see, but isn't current computing limited by the speed of light?

So if quantum computing is instant communication then wouldn't it be instant?

Originally Posted by ScienceNoob

Ahh I see, but isn't current computing limited by the speed of light?

So if quantum computing is instant communication then wouldn't it be instant?

This has nothing to do with the computational power of quantum computing over classical computing. The computational power of quantum computing comes from its ability to perform many calculations simultaneously with far fewer resources than is possible for classical computing.

It should be noted that encryption is based on mathematically "hard" problems, and that while there are known quantum computing algorithms for some hard problems, there are also mathematically hard problems for which there are no known quantum computing algorithms.

There is a good summary here of the sort of problems that quantum computing may be able to solve faster than traditional means:
Quantum computer - Wikipedia, the free encyclopedia