Patent ID: 7840816

Claim:
A method of transferring information material via a network, comprising: at a first device, acquiring a signature for a piece of information material, the signature representing a data characteristic of the piece of information material and being indicative of the information material; providing, by the first device to a second device, the acquired signature; at the second device, identifying an identified piece of information material as the piece of information material from a plurality of pieces of information material stored in the second device from the signature by comparing the signature with signatures stored in the second device in association with respective pieces of information material; transferring, from the second device to the first device, the identified piece of information material, wherein the identified piece of information material is transferred with a watermark embedded therein, the watermark containing an authorization code; and at the first device, performing steps of detecting and extracting from the watermark the authorization code; and in dependence on the authorization code, selectively allowing the first device to duplicate the piece of information material, wherein in the providing step the signature provided by the first device is performed independent of the authorization code, wherein the acquiring step includes acquiring the signature by analyzing at least one location of maximum or minimum values of a signal defining the information material or a histogram of measurable components of the piece of information material.