https://norbt.com/G7SX2X
cool thing is, the encryption [as calced from the answer to the question] is performed only client side in the browser, so norbt server only ever stores encrypted stuff, not even the key phrase (except a 6bit hash of it, to facilitate offline checking, but this is mere usability), so unless norbt is lying or compromised it is pretty secure.
also9 it's fun cause you can store bits of text that can only be read by someone who kinows the answer to the question.
and it even shows a 2D barcode of the URL, except nobody can read those cause mobile platforms are too closed source but otgherwise you could print them on posters and shit
EXAMPLES! LINK US TO THEM