My app uses encryption indirectly as I'm using an encrypted Realm database (and Realm implement the encryption).
I don't therefore know if Realm
"... only uses encryption algorithms provided in iOS for its security features ..."
Realm uses the crypto library and so its reasonable to assume it does use algorithms provided in iOS, but the point is I don't know for a fact if it does or doesn't or if it uses key lengths exceeding 512 bits etc. etc. etc.
So I can answer Apple's question:
".. does your app contain or incorporate cryptography"
as YES as it must do if I'm using a Realm encrypted db.
But I can't answer questions such as
"..Use of encryption is limited to encryption within the operating system"
As I have no idea what Realm is doing with respect to its encryption.
If you have released an app using Realm encryption, what did you do regarding these points when releasing the app, and why?
(A couple of people who are possibly Realm developers have commented on forums that Realm only uses the crypto library and hence only algorithms provided within the OS, but there is no official statement of this on the Realm website. And it can be seen the the Realm code imports Crypto library hence it is very very reasonable to assume this is the fact. But to re-iterate - as an app developer I myself do not categorically know this for a verifiable fact or can refer to an official statement stating this issued by Realm. They have a Legal Considerations section here https://academy.realm.io/posts/tim-oliver-realm-cocoa-tutorial-on-encryption-with-realm/ and they state:
If you are unsure as to whether your app falls within the export compliance exemptions, please contact an attorney
But they don't actually provide sufficient information regarding details of Realm to actually be able to do this.)