And what algorithm is that exactly? They always talk like one exists but I havent seen it yet.
I'm also not an expert on the subject, however the one most commonly talked about at the moment is Lamport signatures, but probably only because they are the most developed. They have a couple of disadvantages, however, most notably their size, which effectively precludes them being used in their current form.
Yeah, not only that but they're really not worth changing over to since they still pin their entire security on a hash function which is no different than bitcoin right now. They say you only use a private key/public key pair in Lamport once but we all know how that turned out in bitcoin. people reuse their addresses they do it all the time.
Lattice-based and Multivariate-based cryptography also frequently mentioned.
I would think one of these two. although after glancing at them i do have my reservations. but i guess it's better than what we have right now with regards to quantum computers.