Up until iOS 10.2, specifiying kSecAttrIsPermanent as YES upon calling SecKeyGeneratePair would persist the key pair permenantly to disk. Starting with iOS 10.3 beta, this is no longer the case. Upon deleting the app, the keypair seems to be deleted as well. A subsequent install and call to SecItemCopyMatching will yield an item not found error.
It was pointed out in this thread: https://forums.developer.apple.com/thread/72271 that the iOS keychain gets wiped upon app deletion starting with iOS 10.3. Is there any means of keeping the kSecAttrIsPermanent constant true to its name?