I created BTCapsule about a year ago, and it might not be exactly what you’re looking for, but maybe it will be helpful.

At first, BTCapsule used the Network Time Protocol (NTP), and when a certain date was met, the information would decrypt. However, I discovered I could trick my computer into thinking it was getting the time from Google while I’m offline.

Then I tried making an executable and storing the encryption key directly into the code. Terrible idea. Someone found it.

Now BTCapsule uses timelock to create two paper wallets. One wallet has a private key that can broadcast the tx immediately, and the other wallet must wait for the timelock to expire before broadcasting. This allows the original owner to always have access, and the recipient to have access in the future if anything happens to the original owner.

I’m not sure about arbitrary data, but I’m sure something could be configured.

BTCapsule for PC:

https://github.com/BTCapsule/BTCapsule

BTCapsule for Android:

https://github.com/BTCapsule/BTCapsule_Android