For a once only use, I thought it would be possible to have an openable/unopenable switch. Once it has been opened it records the fact and can't ever be opened again.
For a cycle, there would be say 10 pre-programmed passwords. Once each one had been used, the program would need the next to open. At the end of the 10 it could either terminate (like once only) or switch back to the first.
-Dormouse
Why not set up a free Fastmail email address setup
with fastmail you can setup 100
onetime use login passwords along with your master password.
just email your data which you want the other person to have into that fastmail and give him one of the onetime use to access that account.
all the other person has to do is login ,access the data and logout you can stop the other person from from doing anything from within the fastmail account ( being an additional account set up just for this you wouldn't have much to access .
Next time you need to send more info just give them another of the 100 passwords.
Onced logged out the password is finished
nogojoe