Accessing encrypted library through Webdav

I have been using Seafile since a few years and would like to help the developer of an app that I use extensively ( who has expressed interest. The idea is to access text files residing inside an encrypted Seafile library through Webdav. The app functions well using an unencrypted Seafile library.
How is the encryption implemented in Seafile and is there any documentation that I could forward to the developer to help him implement safe transmission of the credentials for the encrypted Seafile library?

Thank you

Encrypted libraries cannot be accessed using webdav.

There are two options: use the web API and transfer the password on the server side or use the API to access the raw data, decrypt and combine it (data is stored in blocks, so one file often is composed of multiple blocks).

Thanks for your response.
As I am not a developer myself bear with me here.
If I understand correctly, Option 1 would require accessing the file itself through the web interface and then sending it to the application once the decryption is handled already, e.g. through the Seafile iOS app. No way to access the (decrypted) file directly from inside the app, correct?

Option 2 sounds more powerful but also more complicated to implement. How can the target file be identified or would the entire library be decrypted that way?
Is this inherently less secure than Option 1?

Thanks again