Trilium Notes has a concept of "file notes" which are just notes placed into the tree which can contain binary files. They fill the role of attachments. As any

Trilium Notes has a concept of "file notes" which are just notes placed into the tree which can contain binary files. They fill the role of attachments. As any other kind of note, they are synced to the sync server and all clients. Sync auth is done through HMAC of a timestamp with shared secret. Sync uses HTTP so if sync server is properly configured with TLS, then it is used of course.