In a one word answer: yes. In a few short words: as secure as they will ever be. All online backup solutions use at least 128 bit encryption. This is the same encryption used by all financial institutions worldwide. In fact, there are online backup companies that use 2,048 bit military grade encryption followed by another secure 128 bit encryption process making your data impossible to access for even the most professional hackers. Moreover, your data is stored at a remote location which is protected just as well as the data transfer process.