Some slides on that topic. I am releasing offline tokens feature to nutstash.app this weekend! I plan on writing a short blog about it. Stay tuned!
Discussion
If we can use p2pk locks with ecash when both sender and receiver are offline... that would be ground breaking!
So I am very eager to know more. Currently I can't do it on chasu.me, but I assume there's a technical limitation that I don't fully understand yet. So want to understand more.