They will take the fediverse from my cold dead fucking hands

Oh she absolutely is. She loves belly rubs, head pats, belly pokes aswell!?

Energy requirements scale exponentially on a polynomial time algorithm? That doesnt make sense. I admit however I have only studied quantum computers in relation to what they can do, not how. But I hope what I am saying makes sense.

With regards to extracting the private key from the public key, to my knowledge there is shors algorithm that runs in polynomial time on a quantum computer that solves integer factorisation.

Solve integer factorisation in P and you break RSA in P. I believe there are similar P algorithms that run on quantum computers for the discrete logarithm problem and elliptic curve discrete logarithm problem.

In this sense, if you scale quantum computers resources enough you break modern asymmetric cryptography.

With regards to breaking AES: Quantum computers halve the security. So 256 bit security goes to 128 bits. Still secure.

AES 128 goes to 64 bits of security. Hmmm maybe not secure anymore. Have a read of post quantum cryptography and shors algorithm to see what im on about

EDIT: added important details

Edit 2: so so many typos