Assume I have some Information (i.e. my choice during an election) I want my device to encrypt. At the same time i don't want my device to know the meaning of the information it decrypts.
Example: Before voting I get a ballot and a coding card that indicates which choice represents which candidate. Now the Device can not know which candidate I voted, even if it knows what I "crossed".
My Question: Are there more such methods to hide the Information from my device?