Can't decrypt unsynced library

Hi everyone,

I used a company-hosted Seafile server to store sensitive data. Of course, I encrypted it all in a single library. I then synced this library on my computer.
For various reasons, I didn’t need the library to be synced anymore, so I unsynced it through the client and deleted it on the server.
But now, all my local files are still encrypted, and I cannot decrypt them.
I went to the “Deleted libraries” tab on the web interface, and retrieved my library, but it’s still encrypted, the web UI doesn’t ask for any password, and I can’t read my files (however, there is the lock icon on the library).
How can I retrieve my data? I still know the password I used to encrypt them, but I saw on Seafile’s manual that the encryption process used a randomly generated key that I can’t find anywhere.

I really need those files, I would be most grateful for any help one could give me!

After restoring the library, you should still be able to access it with the original password.