@drgo @excellion@bitcoinhackers.org @grubles Well the really interesting question is what exactly are the security guarantees of this?

I *think* what you want is to have multiple people, cross-signing each other's timestamps. But I need to think a bit about what guarantees that could actually provide under what attack scenarios. Namely, the key thing an attacker can do is delay your satellite reception. And probably not indefinitely! So q: is how to translate that to a constraint on what time it could be?