An electronic book reader has a processor, a display surface, and access
to a memory card upon which is stored a digitally-formatted creative work
such as a book. In addition, the reader has access to a plurality of
precompiled condensed content descriptions of respective books that are
subject to copy restrictions. Before reading a given book, the reader
creates a condensed content description of the book and compares it to
the stored descriptions to determine whether the book is subject to copy
restrictions. If it is, the reader checks for a valid license before
allowing the user to read the book.