I'm not sure about other cryptocoins, but Bitcoin does not use encryption, it only uses authentication, which requires a DSA (Digital Signature Algorithms). Bitcoin's current DSA would in fact be broken by a cryptographically-relevant quantum computer (CRQC). However, there are DSAs - like Lamport signatures and Merkle signatures - known since the 1970s, whose security depends only on the existence of ANY secure hash function. There is no known way to break any widely used hash function using quantum computers. So I reckon that the only change to Bitcoin would be to swap out the current DSA for a different one.
I'm not sure about the downsides of quantum-resistant DSAs.
I'm not sure about other cryptocoins, but Bitcoin does not use encryption, it only uses authentication, which requires a DSA (Digital Signature Algorithms). Bitcoin's current DSA would in fact be broken by a cryptographically-relevant quantum computer (CRQC). However, there are DSAs - like Lamport signatures and Merkle signatures - known since the 1970s, whose security depends only on the existence of ANY secure hash function. There is no known way to break any widely used hash function using quantum computers. So I reckon that the only change to Bitcoin would be to swap out the current DSA for a different one.
I'm not sure about the downsides of quantum-resistant DSAs.
Chat, is this true?