I'm not so jazzed on state-issued UBI myself. It makes the state feel like they're special and I think that leads to bad behavior.
We should use money issued by the most trustworthy entity around, whatever it may be at the time, and the state should have to compete for that spot.
Corporations, government, or billionaires. Those are the three options, pick one.
There's also your friends and family and neighbors--anyone that you know in meatspace and maybe have a reason to trust explicitly.