Quote from: Cnut237 on February 14, 2020, 11:41:16 AM

The difference between the two is the QCs best method of attack. For asymmetric cryptography, Shor's algorithm is the answer. For symmetric, Shor's approach doesn't work, and Grover's algorithm is the approach to use. And whilst Grover does reduce the difficulty somewhat, it is nowhere near as effective for symmetric systems as Shor is for asymmetric systems. I presented the numbers in a different thread, and can share if anyone is interested.

Can you give an example of how to use Shor's algorithm to break ECC? I have a friend that is a professor in QC department in one of the famous Chinese universities, he is unable to answer this question

In fact I have never seen any one that can explain what is a QC and how it actually works, although there are so many material on internet, they all confuse people instead of help them

Schrödinger's cat for example, I think the experiment is designed to show that wave function collapse still happens without observation, since observing cat's status is not directly related to the observing of the particle, which is a prerequisit of wave function collapse in Copenhagen interpretation