I propose adding file encryption to Raidrive.
I think the best way to make this work would be to allow Raidrive to access files the way it normally does, however, if encryption is enabled, when writing to the server, it would encrypt the file, having options to encrypt the content or filename and content.
The user should supply the password for encryption and encryption should use an easily available open-source encryption algorithm so that the user may, if they choose, decrypt the file on their own at some point if Raidrive is not available, or so that other applications can use the same encryption and allow them to access their files.
Any file stored on the server with a certain prefix would be treated as encrypted, with different prefixes used to specify encrypted content only or encrypted file name and content. Since Raidrive would handle this transparently, the files would show their unencrypted names when accessed via Raidrive, while if they looked at their Google Drive (for example) they would see !!B!!<encrypted filename 1>, !!B!!<encrypted file name 2>, !!C!!<normal file name 1>, etc.
A properly chosen algorithm would be one wherein the algorithm iteself is unable to tell successful decryption from failed decryption. This is to make bruteforce decryption of the content more difficult.