I think all the massive b2b custodians are doing MPC. So it's effectively multisig, but not implemented via bitcoin scripting.
Discussion
oh. i was only ever familiar with multi-sig, not MPC. but a quick ask of the googs and i was able to understand it. thanks.
My 80IQ understanding of it is that it's basically Schnorr-like musig (many keys acting onchain as if they were one) but way more complicated because of not-Schnorr math and it seems like every few months some academic paper finds a new maybe-vulnerability. But useful for them because the same approach can secure every shitcoin they custody (including bitcoin) w/the same technique.
Strikes me as a weird place in the Venn diagram where very few players are doing it (and so there's all the usual risks of novel cryptography and limited eyes reviewing/improving the code) BUT the people who are using it are the biggest behemoths out there.
Seems kinda unsettling but also thus far has been totally fine...?