Segwit commitment to post-quantum witness data?

[sipa]

@ajtowns

I think that means each new “style” introduction is a combination soft-fork, block storage and p2p upgrade much like segwit was, with the benefit that all the logic is pre-written with the first new style, so enabling new styles is just “define a new weighting rule, and the activation trigger”. For nodes that upgrade to the new logic late, you’d still need to re-download blocks after activation to get the additional data. That could theoretically involve “invalidating” post-activation blocks that were previously valid if you’re not able to obtain new style data that matched the commitment you already had.

Indeed.

@ajtowns

So in theory just as complicated as segwit’s deployment, but in practice much simpler because it’s just repeating the same logic multiple times, I think.

That, but also no new transaction identifier (like wtxid, with associated P2P logic), and presumably no new weight units (I think 1 WU has enough granularity, so whatever formula is used, I think it can be rounded up to the next WU at the txin, or the tx level).