Receiving device for securely storing a content item, and playback device

• US 7,124,304 B2
• Filed: 03/08/2002
• Issued: 10/17/2006
• Est. Priority Date: 03/12/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Engelen, Dirk Valentinus Rene, Breugom, Michel Ronald, Bel, Hendrik Jan, Van De Poel, Peter, Lokhoff, Gerardus Cornelis Petrus
• Primary Examiner(s): Vu, Kim
• Assistant Examiner(s): Son, Linh L D
• Application Number:
  US10/094,067
• Publication Number:
  US 20020174354A1
• Time in Patent Office: 1,684 Days
• Field of Search: 713/193, 713/165, 380/277, 380/281, 705/59
• US Class Current: 713/193
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00768 wherein copy control information is used, e.g. for indicating whether a content may be copied freely, no more, once, or never, by setting CGMS, SCMS, or CCI flags
• CPC Class Codes: G11B 20/00855 involving a step of exchanging information with a remote server
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; 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 Class Codes: H04N 21/4367 Establishing a secure communication between the client and a peripheral device or smart card
• CPC Class Codes: H04N 21/4788 communicating with other users, e.g. chatting arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/632 using a connection between clients on a wide area network, e.g. setting up a peer-to-peer communication via Internet for retrieving video segments from the hard-disk of other client devices broadcast-related systems characterised by transmission among terminal devices H04H60/80; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A receiving device for securely storing a content item on a storage medium is disclosed. The content item is stored in a secure format, and has an associated license file. The license file is encrypted using public key associated with a group of playback devices, so that each playback device in the group can decrypt the license file and play the content item, but devices outside the group cannot. A playback device can provide a device-specific public key to a Content Distribution Management System (CDMS). The CDMS then returns the secret key for the group encrypted with the public key of the playback device. The playback device then securely obtains the secret key of the group and is subsequently able to decrypt the license file.

Claims

1. A receiving device for securely storing a content item, comprising:

downloading means for downloading the content item,

writing means for writing the downloaded content item to a storage medium, and

licensing means for obtaining a license file from a license server, the license file at least comprising a permission to write the downloaded content item to the storage medium, wherein

license locking means for encrypting the license file with a license key and encrypting the license key with a group key associated with a group of playback devices, and for providing the encrypted license file and the encrypted license key to the writing means for writing the encrypted license file and the encrypted license key to the storage medium,

the group key being encrypted by a distribution manager with a device key of a playback device of the playback devices in response to registration of the playback device with the distribution manager.

2. The receiving device as claimed in claim 1, wherein the group key is the public key of a public/secret key pair.

3. The receiving device as claimed in claim 1, wherein the content item comprises at least one of audio and video data.

4. The receiving device as claimed in claim 1, wherein the license locking means are further arranged for receiving a selection of an identifier of the group and for obtaining the group key associated with the selection from a keyserver.

5. A playback device for playing a content item stored on a storage medium, comprising:

playback means for playing back the content item in accordance with a permission in a license file for the content item, stored on the storage medium, wherein the license file and a license key are stored encrypted on the storage medium,

receiving means for receiving in response to registration of the playback device with a registration means, one or more group decryption keys, the one or more group decryption keys being encrypted by the registration means with a device key of the playback device,

secure storage means for storing the one or more group decryption keys, each group decryption key being associated with a respective group of playback devices,

decoding means for checking whether a stored group decryption key is suitable for decrypting the encrypted license file the license key, and if so,

decrypting the license file using the license key decrypted with the stored group decryption key and providing the decrypted license file to the playback means.

6. The playback device as claimed in claim 5, wherein the license file is stored encrypted with a License Locker Encryption Key (LLEK), said LLEK being stored on the storage medium encrypted with an LLEK encryption key, the one or more decryption keys are LLEK decryption keys, and the decoding means are arranged for checking whether a stored LLEK decryption key is suitable for decrypting the encrypted LLEK, and if so, obtaining the LLEK from the encrypted LLEK using the stored LLEK decryption key, and decrypting the license file using the LLEK.

7. The playback device as claimed in claim 5, wherein the content item comprises at least one of audio and video data.

8. The playback device as claimed in claim 5, wherein the stored decryption key is the secret key of a public/secret key pair.

9. The playback device as claimed in claim 5, wherein the registration means is configured for registering a public key of a public/secret key pair associated with the playback device at a Content Distribution Management System (CDMS), the secret key of said public/secret key pair being stored in the secure storage means, and for receiving a decryption key associated with a group of playback devices encrypted with said public key, decrypting said encrypted decryption key and storing said decryption key in the secure storage means.

10. A computer readable medium storing a computer program for enabling a programmable device when executing said computer program to function as a receiving device, comprising downloading means for downloading a content item,

writing means for writing the downloaded content item to a storage medium,

licensing means for obtaining a license file from a license server, the license file at least comprising a permission to write the downloaded content item to the storage medium, and license locking means for encrypting the license file with license key and encrypting the license key with a group key associated with a group of playback devices, and for providing the encrypted license file and the encrypted license key to the writing means for writing the encrypted license file and the encrypted license key to the storage medium;

the group key being encrypted by a distribution manager with a device key of a playback device of the playback devices in response to registration of the playback device with the distribution manager.

11. A computer readable medium storing a computer program for enabling a programmable device when executing said computer program to function as a playback device, comprising playback means for playing back a content item in accordance with a permission in a license file for the content item, stored on the a storage medium, said playback means including:

receiving means for receiving, in response to registration of the playback device with a registration means, one or more group decryption keys, the one or more group decryption keys being encrypted by the registration means with a device key of the playback device, each group decryption key being associated with a respective group of playback devices,

the license file is and a license key are stored encrypted on the storage medium, and

decoding means for checking whether a stored group decryption keys key is suitable for decrypting the license key, and if so,

decrypting the license file using the license key decrypted with the stored group decryption key and providing the decrypted license file to the playback means.

12. A processor device comprising:

an encryptor to encrypt a license using a license key to form an encrypted license and to encrypt the license key with a group public key associated with a group, said license being associated with a content;

a writer to write said content, said encrypted license and said encrypted license key in a memory for decryption of said encrypted license key with a secret group key associated with said group; and

a reader to read said content;

said secret group key being encrypted by a distribution manager with a device public key of said device in response to registering said device, said reader decrypting said encrypted secret group key using a device secret key of said device, and using said decrypted secret group key to decrypt said encrypted license key;

said decrypted license key being used to decrypt said encrypted license.

13. A processor device for reading content from a memory, said playback device comprising:

decryptor to decrypt an encrypted license key stored on said memory using a first key to form a decrypted license key, and to decrypt an encrypted license stored on said memory using the decrypted license key, said license being associated with said content

wherein said first key is obtained in response to registering said playback device, and

wherein said registering includes providing a second key to a distribution manager, said distribution manager encrypting said first key using said second key to form an encrypted first key which is sent to said playback device for decryption to form said first key, wherein said first key is a group key associated with a group of playback devices, said group key being associated with a group of playback devices.

14. The playback device of claim 13, wherein said first key is a secret key and said second key is a public key.