For me the problem with Zero Knowledge or No Knowledge is, that the website usually don't say, whether they encrypt the content, directory structure, filename o

For me the problem with Zero Knowledge or No Knowledge is, that the website usually don't say, whether they encrypt the content, directory structure, filename or file size. Often it is just the content. It would be great if the services would explain this in more detail. What does SpiderOak encrypt actually? I guess a real "No knowledge" storage would be just a container and you read and write blocks, i. e. the filesystem format is implemented on the client side. Of course this make features such as versioning difficult to implement and probable everything would be a little bit slower. Edit: The post from rarrrrrr explains the technique of Spider Oak and he links to a Blog entry. This is pretty impressive.