sync files in an encrypted folder to a cloud service

Here's what I'm trying to do:

I would like to carry my files, encrypted, on a thumb drive and sync changes to the cloud (I use Google Drive, but am not attached to it, I can switch if necessary).

I've hunted around and can't quite find a solution that works. The files on my thumb drive must be encrypted as they have sensitive client information. And that's where the problem comes in. Since I don't know if I'll have admin rights on a computer I'm limited in what I can use to encrypt files on a thumb drive. The best solution has been to use a secure sandisk usb drive.

Has anyone found a way to sync files in an encrypted folder to a cloud service? I don't care about the type of thumb drive, cloud service or encryption method, I can change easily, I just want to be able to carry my docs, secured, on a usb drive and keep a backup online.