A monitoring apparatus, a computer program and a network are disclosed for monitoring a representation. The representation comprises a first data string. Subsequently, two or more output strings, based on the first data string, are generated by the monitoring apparatus such that the representative can not be reconstructed from just any of the output strings. The output strings are stored at separate storage locations. Each of the locations has different access rights from the other such that a party, authorized to solely access one such location and retrieve the single output string stored there, is unable to access the other location and retrieve the corresponding output string stored there. Consequently, that party, from just the single output string which it can access and retrieve, is unable to reconstruct the entire representation.