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    For most cryptocurrencies, a simple “fix”/hack (for users) is to not use an address more than once (e.g. wallets with change addressses).

    Hashed addresses are basically immune to quantum assaults, revealing your public key is the concern with respect to QM, and that happens each time you send crypto.

    QM-resistant hard forks are being researched/developed by various cryptocurrencies, and will likely be a point of competition.

    Of course, the article fails to point out that this is a problem for all currencies, not just cryptocurrencies. (What do they think banks use to secure themselves? Fairy dust?)

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      Where in a traditional currency would the attack vector be the same? Honestly not seeing it.

      Online banking with secret OTPs and 2FA should be pretty resilient here.

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        Online banking does not use OTPs (one-time-pads), and most users don’t use 2FA.

        Online banking uses what everyone else on the Internet uses: TLS, and TLS uses the same quantum-broken asymmetric crypto that everything else uses. It is, of course, like blockchains, being upgraded to withstand attacks, so I suspect the quantumpocalypse will be, for both TLS and blockchains, somewhat similar to Y2K.

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          I guess the authentication depends on your bank then, doesn’t it?

          In Finland we had unencrypted yet deemed secure enough dialup online banking in the 80s with OTPs. Maybe that’s a curiosity. I have accounts in three banks, two of which require two factors for authentication and one for authorization.

          The third has one factor for login but SMS-based authorization.

          Am I wrong in that an eavesdropper could observe me but not do any harm unless they break the OTP generation and/or steal my phone?

          In which case the fees I pay my bank as an insurance would kick in to remediate losses.

          I could be dumb, but not convinced either.

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            Your bank does not use one time pads. You do not use one time pads.

            All of your bank’s encryption and security will be broken if cryptocurrencies are broken.

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      I have a headcanon that the real Satoshi is someone who dreamed up a working 2nd-preimage attack on SHA2 that takes about 5 minutes to run and, instead of burning it by telling everyone, dreamed up BTC as a really long-winded way of getting rich from it without needing to do anything that’d attract unwanted attention to themselves personally.