<yushanren:matrix.org> Hi guys, I have learned something about FCMP++, and I have a long confused question. Do old blocks quantum resistant? If hard fork happens, do I need to move my funds to a new wallet?

<jpk68:matrix.org> FCMP++ is not quantum-resistant, but the Carrot key hierarchy (which will likely ship with it) has some quantum forward-secrecy benefits

<yushanren:matrix.org> Okay, grok says the same. But what about the first question without considering fcmp++? Is there one way to keep privacy for old blocks?

<boog900> FCMP++ adds a blindng factor to key images making them quantum private, as then a key image does not allow you to link what output spent it with a QC

> Is there one way to keep privacy for old blocks?

you already have exposed the necessary data for a QC opponent

you can't undo exposing it

you keep existing privacy set against non-QC

it's also not about the blocks but transactions.

<yushanren:matrix.org> What is the best time to move funds? Do I have to?

read up/see github.com/jeffro256/carrot/blob/master/carrot.md, AI is likely to get it wrong due to the specifics/novel data

you don't have to. read that and see what the new wallet hierarchy would offer if you decide to transition

you won't be able to do before the upgrade happens, which is still quite a ways

<yushanren:matrix.org> Okay

note a QC opponent would be able to still obtain old information on the specific cases before the upgrade, even if you move outputs elsewhere after

<yushanren:matrix.org> If someone uses quantum computers to decrypt old blockchain data, what will he get? Everything or nothing?

<yushanren:matrix.org> DataHoarder: It’s like the optional privacy part.