**1.2.1 Practical tasks of identification**

The immediate practical task of identification of records can be put in various variants. In practice of ascertainment and protection of copyrights, and also detections of a source of media object the most often situations are when record on the initial carrier is exposed to identification - ascertainment or a refutation of the fact of an origin of record from the presented device is required, or the record copied on other carrier (possibly with automatic format conversion, compression of dynamic range or other variants of postprocessing) is exposed to identification. In the latter case initial record obtaining, as a rule is complicated, and frequently impossible. It is required to determine a record ownership to the device presented by means of another records set certainly acquired with it.
