SpiderOak puts data privacy and security above all else, priding itself on the fact that no one -- not even the company itself -- has access to client data except the client. Great for government agencies, financial institutions and other highly security-conscious organizations, SpiderOak also stands out for its "zero-knowledge" policy. A developer of de-duplication and central storage repository software, SpiderOak combines encrypted cloud storage with the ability to back up, sync, access and share any type of data. SpiderOak is available for Android, iOS, Linux, Mac OS X and Windows.
Once signed up, an encryption key is issued that's unique to each user, and only their password will provide access to it. The first 2 GB are free; after that, SpiderOak costs $10 per month for 100 GB or $600 per month per TB for an unlimited number of users. This is one, secure cloud-based storage service; just don't lose your password.