Copy protection of data

Abstract

A copyright protection scheme is provided in which data is downloaded from a server 1, typically over the World Wide Web 2 to a client 3, for presentation to a user. The downloaded data is cryptographically protected, by encryption and hashing. When displayed by the client, storing and copying functions are selectively disabled in respect of the data, in order to prevent unauthorised copying.

1 .- 27 . (canceled)  
   
   
       28 . A method of downloading data from a server to a client, the method comprising: 
 transmitting an applet from the server to the client, the applet including at least a hashing algorithm, an encryption algorithm, and an encryption key;    receiving, at the server, a file request for the data from the client, the file request being generated by execution of the applet at the client;    hashing, at the server, the requested data using a copy of hashing algorithm that was previously transmitted to the client as part of the applet;    encrypting, at the server, the requested data using a copy of the encryption algorithm and the encryption key that were previously transmitted to the client as part of the applet; and    wrapping the hashed and encrypted data in a file and transmitting the wrapped filed to the client.    
   
   
       29 . The method as in  claim 28  further comprising watermarking the requested data with an identifier associated with the client.  
   
   
       30 . The method as in  claim 28  wherein the requested data includes a header and embedded file information, and said wrapping the data includes: 
 generating a first hash value and including the first generated hash value in the header of the requested data to enable an integrity of a content of the header to be verified at the client; and    generating a second hash value and including the second generated hash value in the embedded file information of the requested data to enable an integrity of a content of the embedded file information to be verified at the client.    
   
   
       31 . A server for downloading data to a client, said server comprising: 
 an output which transmits an applet to the client, the applet including at least a hashing algorithm, an encryption algorithm, and an encryption key;    an input which receives a file request for the data from the client, the file request being generated by execution of the applet at the client;    a processor which: 
 hashes the requested data using a copy of hashing algorithm that was previously transmitted to the client as part of the applet;  
 encrypts the requested data using a copy of the encryption algorithm and the encryption key that were previously transmitted to the client as part of the applet; and  
 wraps the hashed and encrypted data in a file and transmitting the wrapped filed to the client.  
   
   
   
       32 . The server as in  claim 31  wherein the processor watermarks the requested data with an identifier associated with the client.  
   
   
       33 . The server as in  claim 31  wherein the requested data includes a header and embedded file information, and the processor, when wrapping the data: 
 generates a first hash value and includes the first generated hash value in the header of the requested data to enable an integrity of a content of the header to be verified at the client; and    generates a second hash value and includes the second generated hash value in the embedded file information of the requested data to enable an integrity of a content of the embedded file information to be verified at the client.