Hello @chtsai - Some versions of iOS shipped an undocumented encryption feature in the system SQLite library. We originally identified this behavior in iOS 13 and 14. The encryption function does not use SQLCipher, but it does respond to PRAGMA key. As far as we can tell, this undocumented encryption feature was removed sometime after iOS 15.0, likely because it was not intended for application use.
Coming back to SQLCipher, unfortunately if the database is not encrypted using SQLCipher, the library doesn’t know how to open it and can’t convert or re-encrypt it. Unfortunately, you may need to remove the database and recreate from scratch in that case.