Why not just send the Decryption key after X time has elapsed? You do not even trust yourself? If you really want to make it vulnerable to 51% attacks you can

Why not just send the Decryption key after X time has elapsed? You do not even trust yourself? If you really want to make it vulnerable to 51% attacks you can also split the cypher and send it to a lot of different people to be reassembled in a later date.