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And the public keys neither, since a quantum computer can reverse engineer the private key from the public.

So a bitcoin address is not recommended to be reused.

Does this mean we need to create a quantum-resistant bitcoin copy? :P

No, bitcoin is pretty much quantum resistant if you don't reuse the address.

So if you have a big stash of coins, when you send out money from that address, send back all the change money to another address of yours that was un-used.

So your address where the big money is stored should not have an outgoing transaction.

Keep it as private as your privates!

Except don't show your private key to your significant other either. :P