Method and apparatus for recorded digital data protection via media volume

• US 6,813,709 B1
• Filed: 03/24/2000
• Issued: 11/02/2004
• Est. Priority Date: 09/25/1997
• Status: Expired due to Fees

• Current Assignee: Canal+ Technologies (Vantiva SA)
• Original Assignee: Canal+Societe Anonyme
• Inventors: Benardeau, Christian
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Baum, Ronald
• Application Number:
  US09/534,181
• Time in Patent Office: 1,684 Days
• Field of Search: 713/190-202, 705/55-58, 369/59.25
• US Class Current: 713/172
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying

Abstract

A method of restricting access to recorded digital data on a digital support medium (2) using an integrated circuit e.g. on a smart card (4) containing a first decryption key (Kf) characterized in encrypting with a corresponding encryption key (Kf) one or more elements of the volume descripter (V) of the support medium (2), recording the encrypted elements of the volume descripter together with non-encrypted data on the support medium and, when accessing the support medium (2), using the integrated circuit decryption key (Kf) to decrypt the encrypted elements of the volume descripter (V) and to supply a reader (5) with these elements so as to permit the reading and/or writing of non-encrypted data on the support medium (2).

Claims

1. A method of restricting access to recorded digital data on a support medium using an integrated circuit associated with the support medium containing a first decryption key, comprising:

encrypting one or more elements of a volume descriptor of the support medium with a corresponding encryption key;

recording the encrypted one or more elements of the volume descriptor describing characteristics of non-encrypted data together with said non-encrypted data on the support medium; and

when accessing the support medium,

using the first decryption key of the integrated circuit associated with the support medium to decrypt the encrypted one or more elements of the volume descriptor and supply a reader with the decrypted one or more elements of the volume descriptor so as to permit reading and/or writing of the non-encrypted data on the support medium,

re-encrypting the volume elements by the integrated circuit according to a new key generated and stored in the integrated circuit, and

recording the re-encrypted volume elements on the medium by the reader, replacing the previously encrypted values,

wherein the integrated circuit and the support medium are removable from the reader.

2. The method of restricting access to recorded digital data as claimed in claim 1 in which the integrated circuit is embedded in a smart card, the smart card acting to decrypt the encrypted volume elements and to pass the encrypted volume elements to the reader so as to permit reading and/or writing of the recorded data.

3. The method of restricting access to recorded digital data as claimed in claim 1 in which the first key is stored in the integrated circuit that is embedded in the housing of the support medium.

4. The method of restricting access to recorded digital data as claimed in claim 1 in which the first key comprises a key diversified by a manufacturing constant representing a value associated with the identity of the support medium or the recorded data.

5. The method of restricting access to recorded digital data as claimed in claim 1 in which the first key is usable with a symmetric encryption algorithm.

6. The method of restricting access to recorded digital data as claimed in claim 1 in which the new key is generated by a random or psuedo-random number generator in the integrated circuit.

7. The method of restricting access to recorded digital data as claimed in claim 1 in which the new key generated by the integrated circuit is diversified by a value associated with the identity of the reader read by the integrated circuit from the reader.

8. The method of restricting access to recorded digital data as claimed in claim 7 in which the integrated circuit compares a first reader identity value stored on the support medium with a second reader identity read from the reader and, in the event of a difference between the first reader identity and the second reader identity, decrypts the volume elements using the first reader identity value from the support medium and thereafter re-encrypts the volume elements using the second reader identity value taken from the reader.

9. The method of restricting access to recorded digital data as claimed in claim 8 in which the new reader identity value replaces the previous reader identity value stored on the support medium, wherein only a pre-determined number of replacements of the identity value are permitted.

10. The method of restricting access to recorded digital data as claimed in claim 8 in which the new reader identity value is stored in a list of authorized readers on the support medium, wherein only a pre-determined number of readers allowed in the list.

11. The method of restricting access to recorded digital data as claimed in claim 1 in which the support medium is pre-recorded with non-encrypted digital data.

12. The method of restricting access to recorded digital data as claimed in claim 1 in which the support medium is blank prior to its first insertion in the reader, the presence of the integrated circuit being necessary in order to decrypt the volume elements before the reader is allowed to write any data onto the blank medium.

13. The method of restricting access to recorded digital data as claimed in claim 1 in which the data comprises audiovisual data.

14. A method of manufacturing a support medium with an integrated circuit associated with the support medium, the support medium being conditionally accessible by a reader, the method comprising:

encrypting one or more of the elements of a volume descriptor associated with the support medium by means of a first key; and

storing an equivalent of the first key necessary to decrypt the one or more elements of the volume descriptor describing characteristics of non-encrypted data on the integrated circuit associated with the support medium,

wherein the integrated circuit is embedded in the housing of the support medium and the support medium removable from the reader.

15. A method of restricting access to recorded digital data on a support medium using an integrated circuit associated with the support medium containing a first decryption key diversified by a manufacturing constant representing a value associated with the identity of the support medium or the recorded data, comprising:

encrypting one or more elements of a volume descriptor of the support medium with a corresponding encryption key;

recording the encrypted one or more elements of the volume descriptor describing characteristics of non-encrypted data together with said non-encrypted data on the support medium; and

when accessing the support medium, using the first decryption key of the integrated circuit associated with the support medium to decrypt the encrypted one or more elements of the volume descriptor and supply a reader with the decrypted one or more elements of the volume descriptor so as to permit reading and/or writing of the non-encrypted data on the support medium,

wherein the integrated circuit and the support medium are removable from the reader.

16. The method of restricting access to recorded digital data as claimed claim 15 in which the volume elements are re-encrypted by the integrated circuit according to a new key generated and stored in the integrated circuit, the encrypted volume elements being thereafter recorded on the medium by the reader, replacing the previously encrypted values.