Compression and decompression techniques for DRM license information delivery

Patent metadata

Field	Value
Publication number	US-9641910-B2
Application number	US-201113273499-A
Country	US
Kind code	B2
Filing date	Oct 14, 2011
Priority date	Oct 14, 2010
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

Techniques for compressing and decompressing license information for Digital Rights Management are described. A method implementation of a technique of creating for a plurality of client devices or client device groups compressed license information comprises the steps of creating a template and a table. The table comprises at least one first license part common to licenses for the plurality of client devices or client device groups and one or more placeholders for one or more second license parts specific for a dedicated client device or client device group. The table comprises, for each client device or client device group and for a given placeholder, replacement information specific for that client device or client device group. The method further comprises sending the template and table for delivery as compressed license information to the client devices or client device groups.

First claim

The invention claimed is:

1. A method of creating, for a plurality of client devices or client device groups, compressed license information for Digital Rights Management, the method comprising:
creating a template comprising:
at least one first license part common to licenses for the plurality of client devices or client device groups; and
one or more placeholders for one or more second license parts specific for a dedicated client device or client device group, wherein a dedicated license specific to the dedicated client device or client device group comprises both the at least one first license part and the one or more second license parts; and

creating a common first table comprising replacement information specific:
for each respective client device or client device group in the plurality of client devices or client device groups; and
for replacing a given placeholder of the one or more placeholders in the template with a given second license part of the one or more second license parts to reconstruct the dedicated license; and

sending at least the template and the common first table for delivery as compressed license information to the client devices or client device groups.

2. The method of claim 1 , wherein creating the common first table comprises decoding a BASE64 encoded string to binary data as replacement information.

3. The method of claim 1 , further comprising providing a first encoding parameter that defines a required encoding of the replacement information when replacing the one or more placeholders in the template with the replacement information, wherein the common first table also includes the first encoding parameter.

4. The method of claim 3 , wherein the first encoding parameter defines whether the replacement information is to be BASE 64 encoded or used in a plain format or in an integer format.

5. The method of claim 1 , further comprising encoding the template, or data included therein.

6. The method of claim 5 , further comprising providing a second encoding parameter that defines the encoding of the template, or of the data included therein, wherein the template also includes the second encoding parameter.

7. The method of claim 1 , further comprising:
creating a second table associating a reference index with each placeholder;
wherein the common first table associates, for each client device or client device group and for a given placeholder, replacement information specific for that each respective client device or client device group with the reference index of that a given placeholder.

8. The method of claim 1 , wherein the license information comprises one or more cryptographic content keys for Digital Rights Management, and wherein the replacement information contains the one or more cryptographic content keys.

9. The method of claim 8 , wherein each of the one or more cryptographic content keys is encrypted for a specific client device or client device group.

10. The method of claim 1 , wherein the common first table contains a device identifier.

11. The method of claim 1 , further comprising associating at least the template and the common first table with at least one association identifier that allows associating at least the template and the common first table with each other.

12. The method of claim 11 , wherein the association identifier is a license identifier.

13. The method of claim 1 , wherein a predefined value of the association identifier is configured to indicate that the license is complete and does not contain any placeholders to be replaced.

14. The method of claim 1 , wherein the at least one first license part includes at least one of information regarding a common overall structure and common control information.

15. The method of claim 1 , further comprising embedding at least the template and the common first table into a content stream.

16. The method of claim 15 , further comprising sending the content stream with the embedded template and the embedded common first table to the client devices or client device groups.

17. The method of claim 15 , wherein the content stream conforms to the MPEG2-TS specification.

18. The method of claim 1 , wherein at least the template and the common first table are embedded in one or more Entitlement Management Messages that conform to the Marlin Broadband specification.

19. The method of claim 1 , wherein the license information conforms to the Marlin Broadband specification.

20. A method of decompressing compressed license information for a given client device or client device group for Digital Rights Management, the method comprising:
receiving compressed license information, the license information comprising:
a template comprising:
at least one first license part common to licenses for a plurality of client devices or client device groups; and
one or more placeholders for one or more second license parts specific for a dedicated client device or client device group, wherein a dedicated license specific to the dedicated client device or client device group comprises both the at least one first license part and the one or more second license parts; and

a common first table comprising replacement information specific:
for each respective client device or client device group in the plurality of client devices or client device groups; and
for replacing a given placeholder of the one or more placeholders in the template with a given second license part of the one or more second license parts to reconstruct the dedicated license; and

reconstructing the dedicated license by replacing the one or more placeholders in the template with the replacement information from the common first table for the given client device or client device group.

21. The method of claim 20 , further comprising processing the replacement information prior to reconstructing the dedicated license.

22. The method of claim 20 , wherein the common first table further comprises a first encoding parameter that defines a required encoding of the replacement information when replacing the one or more placeholders in the template with the replacement information.

23. The method of claim 22 , wherein the first encoding parameter defines whether the replacement information is to be BASE64 encoded or used in a plain format or in integer format.

24. The method of claim 20 , further comprising decoding the template, or data included therein.

25. The method of claim 24 , wherein the template further comprises a second encoding parameter that defines the encoding of the template, or of the data included therein, and further comprising decoding the template or the data included therein in accordance with the second encoding parameter.

26. The method of claim 20 , further comprising:
receiving a second table associating a reference index with each placeholder;
wherein the common first table associates, for each client device or client device group and for a given placeholder, the replacement information specific for that client device or client device group with the reference index of that placeholder; and
wherein reconstructing the dedicated license comprises replacing the one or more placeholders in the template with the replacement information from the common first table for the given client device or client device group according to one or more reference indices from the second table.

27. The method of

Assignees

• Catrein Daniel
• ERICSSON TELEFON AB L M (publ)

Inventors

• Catrein Daniel

Classifications

• H04L9/0891

  Revocation or update of secret information, e.g. encryption key update or rekeying · CPC title

• H04L63/10

  for controlling access to devices or network resources · CPC title

• H04L2209/603

  Digital right managament [DRM] · CPC title

• H04N21/4627

  Rights management {associated to the content (security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08)} · CPC title

• H04N21/8355 Primary

  involving usage data, e.g. number of copies or viewings allowed · CPC title