Oddbean new post about login | logout Could just put the date right in the token to, so every signature from the mint commits to the date.
Problem is the mint doesn't see what it's signing (the user could put anything in there). Would need crypto magic to put it in there and still prove some (zk) property of the blinded message (Pedersen commitments). The cleartext signature sounds like an easy way to achieve the same thing without changing too much in the protocol, probably can be done backwards compatible.