So the general consensus is somewhere along the lines of "if quantum computing cracks Bitcoin, there will be bigger and more serious problems to worry about"?
Pretty close. Here are the facts:
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3) For certain kinds of problems, QC can provide quadratic speedup, which is a massive speedup. For symmetric ciphers, this probably just means you double your key size - where 128 bits of security used to be sufficient, now you need 256. No big deal. The real problem is with public-key encryption. But lay-people often forget that the quantum speedup blade cuts both ways. We can build
encryption systems which take advantage of quantum speedup and make quantum cryptanalysis of PKE quadratically more difficult, mooting the theoretical advantage that cryptanalysts get from quantum speedup.
In fact, this is why Bitcoin uses the public-key hash instead of the public-key itself and recommends against address-reuse; in the event of working, at-scale QC, your coins are still secured behind 128-bit-equivalent security as long as you don't reuse addresses or publish the public-keys for your addresses.
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I'm sorry to short your message but I would know at the underlined sentence if I have good understood the point.
The fact that Public Key and Bitcoin Address are different is not a safeguard against Quantum computing, because when you sign a transaction you are revealing on the blockchain your Publickey, so that Adress can be exposed to QC attack, is that correct?
My doubt is when you speak about "address-reuse": what do you mean with that? I have a cold storage paper wallet ecrypted via BIP0038 where I periodically put some cash into that. I've never spent BTC on that but there is not a single but multiple input transactions, so there are multiple utxo transactions on the blockchain.
Until I don't spend bitcoin is it still secured or not? Should I use a cold storage paper wallet for every transaction? Thanks in advance