What we mean by "security" is something different. The service provider never has the ability to read or modify your data in the first place -- never. If you use Tahoe-LAFS, then all of the threats described above are non-issues to you. Not only is it easy and inexpensive for the service provider to maintain the security of your data, but in fact they couldn't violate its security if they tried. This is what we call provider-independent security.

"Tahoe": a secure, decentralized, fault-tolerant filesystem.