And where did I ever say that? Quantum computers could solve certain types of problems because algorithms are known for those certain types of problems.
Exactly. They can solve "certain types of problems" but they can't magically decrease the 128-bit security of a EC private key to 80 bit.
I didn't say it was invented later. I said Satoshi invented it. Is that wrong?
It sounded to me like you were suggesting it came later.
your'e trying to lump in other things along with bitcoin to try and make it sound like someone would have to be irrational to attack bitcoin using a quantum computer. perhaps bitcoin is a simpler target to go after than some of the things you mentioned. ever think of that?
The point is to say cryptography is not going to be broken as easily as you think otherwise we wouldn't have built so much on top of it. Historically this has also been true. We can always foresee the technical developments including hardware capabilities that could lead to weakening a cryptography algorithm and we have always been replacing them with stronger ones for the past thousand+ years.
Sure you can. You have can have 256 bits as long as you don't leak the public key. Surprised you don't realize that.
The key will still provide 128-bits of security.