Your encrypted messages can only be viewed up until 23:59:59(UTC) on the day you generate them. After that, they'll no longer be viewable. Whilst I'm still faffing around making this, I will probably work on making the messages self-destruct 24 hours from the moment you make them.
Expiration: 23 hours, 32 minutes.
dhTwcrypt, made by @dalehay