Secured back end [Encryption/Decryption]

Hi all,
I am developing a small software which search from a database and display a result.
There will be two columns product ID and Product Year. when the user enters if the year will be retrieved.
Now I need to give the data with the installation package. My problem is , I dont want the user to see the data and I want to make the data secured.

Can you help me explaining which Data Back end is suitable like CSV,XML or EXCEL?
If its a Encryption/ Decryption then I have this problem
do I have to decrypt the file each and every time when the users wants to search?

please help me with a solution

You can use a database which is capable of encrypting the content. MS Access could be the easiest and lighweight solution if you need only limited functionality.

HI I have only one functionality to be more precise..
One input and one output..