That is correct, the AP2 module does not have built-in encryption.
You can add this at the application level if you desire, in your own microcontroller.
The C7 module does have built-in AES128 encryption for file transfers.
http://www.thisisant.com/pages/products/c7-modules
Are you developing a custom application, or do you want to work with an ANT+ (interoperable) device?