Sync and encrypt folders?

I'd like to sync a folder (with many subfolders and files) with a destination folder, but *encrypt* the files in the destination folder.

The use case is that the destination folder would used as the source for a cloud backup, so I'd like to have the files encrypted before they move to the cloud.

I only want to (re)encrypted new/modified files, so that the cloud sync only needs to upload the changed delta.

Is this possible with Hazel? I couldn't see any encryption actions. Would I have to write a custom JavaScript action (or something similar)?

And, can it handle sync a large volume of files? Not sure if that's a use case for it or if I'd be pushing it too far.

The Sync action is based on rsync, so should behave similarly when syncing a large number of files.

As for encrypting, there's no built-in action for that but you can use a script. Or alternatively, you can use an encrypted disk image though syncing that would require syncing the whole disk image every time, I suspect.