Secure information retrieval and update

A secure storage module of a client device interacts with a set of secure storage servers to securely store data items of the client on the servers, such that no individual server has the data in readable (non-obfuscated) form. Additionally, the client secure storage module and the servers interact to allow the client device to read a given portion of the original data items from the servers, such that none of the servers can determine which portion of the original data is being requested. Similarly, the interactions of the client secure storage module and the servers allows the client device to update a given portion of the original data on the servers to a new value, such that none of the servers can determine which portion is being updated and that none of the servers can determine either the prior value or new value or the difference between the new value and the prior value.