The disclosed methods provide a reliable and secure method of automatically backing up a client's data on a personal computer by using excess storage capacity on a set of one or more predetermined computers, without the need for dedicated servers, server disks, removable storage media, or intervention by a user to assist with the storage devices. The methods of the present invention permit a user, be it an individual or a large company, to inexpensively and securely back up information without the need to acquire additional expensive hardware.