Cryptsync is really great. You set it up so that it syncs from a source directory to a "backup" directory that exists in a folder that is cloud enabled, such as Dropbox, Box, or GDrive. The files that you write into your source are encrypted and dropped in the backup, which is then synced to the cloud. It allows me to keep backups of everything in the cloud of my choice, to have it fully encrypted, and to only upload the changes. It's a perfect tool for me.