SQLite Database Encryption
By default, SQLite databases created by PSPDFKit are not encrypted, but they are still protected by iOS data protection, just like all the data in an application is. In case you need to add an additional level of security, there are SQLite extensions that enable database encryption. These extensions encrypt database content and SQLite metadata.
One such extension is the SQLite Encryption Extension. This extension requires an SEE license.
Another alternative implementation is SQLCipher, which is an open source project with a BSD-style license. To integrate SQLCipher, follow the instructions for either the commercial edition or the community edition.
You can read more about how PSPDFKit integrates with your custom SQLite library here.