A cryptographically signed filesystem provides a central database resident on a server that contains database objects. The server creates startup software to be installed in a client system's read only memory. The startup software contains a hash value for a second stage loader. The server also creates software for a bootstrap loader object which typically contains the operating system for a client system and also the bootstrap loader's hash value and a digital signature that is unique to the server. The startup software and objects created by the server are initially installed on a client device at the time of manufacture. The server can update a client's bootstrap loader and root filesystem at any time through the transmission of slices.