Steganography is a different type of decryption from Cryptography as a crypto-system doesn't conceal it's true purpose. A cypto system can be interacted with by anybody however almost impossible to access without the vital key. A Steganography system is different as it aims at concealing the existence of the message all together therefore not attracting the attention of third parties.
An example of a Steganography encryption method would be writing in invisible ink, the message and method wouldn't be known by third parties however the receiver would have knowledge of the method therefore enabling them to decrypt the message.
Cryptography is the encryption method i'm using for my project as I think a Steganography method wouldn't be clear to the audience. The Cryptography method i'm using may seem unfamiliar to the user at first but as they move the trackable objects around and interact with the display they should notice the display reacting to the interaction of the user and as a result understand what they need to do to solve the puzzle.
The Cryptography method I'm using in my display does consist of a secret key. The secret key consists of five sets of numbers, these numbers can be inputted into the sketch by positioning the trackable objects at certain distances from each other. I believe this cypto-system would be very difficult to decrypt if I didn't provide visual confirmation for each part of the puzzle which is completed.