This flow chart will probably help you get on the right track. It indicates that if the encryption is limited to copyright protection / intellectual property then it is exempt from the review. I got to this flow chart from the BIS homepage. That page is referenced by the FAQ entitled World Wide Trade Compliance for the App Store in iTunes connect which states you can claim exemption:
(i) if you determine that your app is not classified under Category 5, Part 2 of the EAR based on the guidance provided by BIS
Hope this helps clear things up a bit.
EDIT Another interesting section is this, you can claim exemption if:
(iii) your app uses, accesses, implements or incorporates encryption with key lengths not exceeding 56 bits symmetric, 512 bits asymmetric and/or 112 bit elliptic curve
