I'm looking for a simple, remote, locally-encrypted storage solution

I want to store a handful of gigabytes of data online while keeping it easy to use, so I need a workflow/solution that:

1. Lets me read/write directly (i.e. it shouldn't simply be a backup solution);

2. Encrypts/decrypts files on the fly, locally;

3. Makes it easy to explore/download each file/folder separately.

Mega does all of this, but then I have to trust Mega that it actually can't read the files. I'm looking for a solution that decouples the storage provider from the encryption.