Each document that you store in Izimi is split into small, encrypted fragments. All these small fragments are distributed over many disks, in such a way that if someone should take possession of a disk, even after centuries of decryption of fragments, it would still be impossible for anyone to access your documents, since they would only have tiny fragments.
All the documents uploaded to Izimi are subject to prior control. That means that we check each added document to make sure that it does not contain any malware or virus. Even if a virus should slip through the net, the files are immediately saved in a non-executable environment — imagine they are frozen in time, even if they contain a virus, the virus cannot spread.