Crypto transactions featured heavily in Stross' Neptune's Brood for synchronizing transactions over interstellar distances: https://en.m.wikipedia.org/wiki/Nep

Crypto transactions featured heavily in Stross' Neptune's Brood for synchronizing transactions over interstellar distances: https://en.m.wikipedia.org/wiki/Neptune%27s_Brood https://en.m.wikipedia.org/wiki/Neptune%27s_Brood Money was split into slow, medium, and fast variants -- the former of which was subject to speed of light limitations in the key signing for verification.