The problem that Google Solved with Quantum Supremacy

The problem has to do with sampling, random numbers and probability distributions, so it is of interest to our community. As Scott Aaronson describes it in his blog, here is the problem:

You can read more here, including answers to the following questions:

• But if the quantum computer is just executing some random garbage circuit, whose only purpose is to be hard to simulate classically, then who cares? Isn’t this a big overhyped nothingburger?
• If Google has indeed achieved quantum supremacy, does that mean that now “no code is uncrackable”, as Democratic presidential candidate Andrew Yang recently tweeted?
• If quantum supremacy calculations just involve sampling from probability distributions, how do you check that they were done correctly?
• Is there a mathematical proof that no fast classical algorithm could possibly spoof the results of a sampling-based quantum supremacy experiment?
• Does sampling-based quantum supremacy have any applications in itself?
• If the quantum supremacy experiments are just generating random bits, isn’t that uninteresting? Isn’t it trivial to convert qubits into random bits, just by measuring them?

This topic was also covered on Quora, here. The leaked NASA document with all the details, can be found here.