Encryption means really nothing. Ultimately, if you need to show or run it, your local computer needs to be able to decrypt it before use, which means the decryption keys must be available too at the same local computer. In other words, you'll have to send the keys of the door along or you won't be able to use or show the house.
That means any dedicated person is going to be able to decrypt it as well.
Given enough users, there is going to be at least one such dedicated person.
As frob said, the only really secure way is to not give the secret stuff away at all. You can't reverse engineer what is not there.