The excerpt in bold is taken from iOS documentation:
Data protection is enabled automatically when the user sets an active passcode for the device. The application read and writes data, the system encrypts and decrypts behind the scenes. The encryption and decryption process are automatic.
Apple provides different levels of data protection to apply to files. HxGN EAM for Transit applies the highest level which is "Complete" - The application file is only accessible when the device is unlocked.