We use SSL encryption, which is what’s used for online banking. But it doesn’t stop there. Not only are your files encrypted during the upload, download and transfer stages, but they’re perpetually secure in storage.
That means that, against all odds, someone was able to physically access Amazon’s file servers* – they couldn’t read the files without a randomly generated, dynamic, extremely long secret key.
* If you can think of it, Amazon has it covered. You can read about their security measures here.