Information terminal

• US 20070124245A1
• Filed: 08/02/2006
• Published: 05/31/2007
• Est. Priority Date: 11/29/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sato, Jun, Watanabe, Keiko, Terauchi, Toru
• Granted Patent: US 8,064,603 B2
• Time in Patent Office: Days
• US Class Current: 705/50
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• 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 21/4627 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 Class Codes: H04N 21/63345 by transmitting keys key distribution for secret or secure communication H04L9/08; network support of key management H04L63/06
• 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

When content owned by a source device are played back in a rendering device, a content key is transferred from the source device to the rendering device via a secure session every time playback is carried out. Then, encoded content are decoded and played back to be outputted by using the transferred content key so as to discard the content key after the end of playback.

Claims

1. An information terminal acting as a source terminal and rendering terminal comprising:

when acting as the source terminal, the information terminal executes;

storing encoded content and a rights object including rights information assigned to the content and key information used to encode the content;

establishing a secure session with a information terminal acting as the rendering terminal and generating a common key; and

encoding the key information included in the rights object corresponding to the encoded content by the generated common key, and transmitting the encoded key information to the information terminal acting as the rendering terminal via the secure session, and when acting as the rendering terminal, the information terminal executes;

acquiring the encoded content;

establishing the secure session with the information terminal the acting as source terminal and generating a common key;

receiving the encoded key information transmitted from the information terminal acting as the source terminal via the secure session;

decoding the received encoded key information by using the generated common key;

decoding and playing back the encoded content by using the decoded key information; and

discarding the key information after the end of playback of the decoded content.

2. The information terminal according to claim 1, wherein the information terminal acting as the source terminal further executes, when the rights object includes information for limiting a playback count, decrementing the information for limiting the playback count every time the decoded key information is transmitted to the information terminal acting as the rendering terminal or every time playback end notification of encoded content is sent from the information terminal acting as the rendering terminal.

3. The information terminal according to claim 1, wherein the information terminal acting the source terminal further executes, transmitting invalid key information to the information terminal acting as the rendering terminal after playback of the encoded content has terminated in the information terminal acting as the rendering terminal, and

the information terminal acting as the rendering terminal further executes,

receiving invalid key information transmitted from the information terminal acting as the source terminal, and

rewriting the key information used to decode the encoded content into the received invalid key information.

4. An information terminal acting as a source terminal and a rendering terminal comprising:

when acting as the source terminal, the information terminal executes;

storing encoded content and a rights object including rights information assigned to the content and key information used to encode the content;

acquiring a public key of the information terminal from the information terminal acting as the rendering terminal; and

encoding the key information included in the rights object corresponding to the encoded content by the acquired public key, and transmitting the encoded key information to the information terminal acting as the rendering terminal, and

when acting as the rendering terminal, the information terminal executes;

acquiring the encoded content targeted for playback;

receiving the encoded key information transmitted from the information terminal acting as the source terminal, and decoding the received encoded key information by a secret key paired with the public key;

decoding and playing back the encoded content by using the decoded key information; and

discarding the key information after the end of playback of the decoded content.

5. The information terminal according to claim 4, wherein the information terminal acting as the source terminal further executes, when the rights object includes information for limiting a playback count, decrementing the information for limiting the playback count every time the decoded key information is transmitted to the information terminal acting as the rendering terminal or every time playback end notification of encoded content is sent from the information terminal acting as the rendering terminal.

6. An information terminal acting as a source terminal and a rendering terminal comprising:

when acting as the source terminal, the information terminal executes;

storing encoded content and a rights object including rights information assigned to the content and key information used to encode the content;

sending a public key of the information terminal to an information terminal acting as a rendering terminal, and receiving and storing a public key of the information terminal sent from the information terminal acting as the rendering terminal; and

encoding the key information included in the rights object corresponding to the encoded content by the stored public key of the information terminal acting as the rendering terminal, and transmitting the encoded key information to the information terminal acting as the rendering terminal, and

when acting as the rendering terminal, the information terminal executes;

sending a public key of the information terminal to the information terminal acting as the source terminal, and receiving and storing a public key of the information terminal to be sent from the information terminal acting as the source terminal;

acquiring the encoded content targeted for playback;

receiving the encoded key information transmitted from the information terminal acting as the source terminal, and decoding the received encoded key information by a secret key paired with the public key of the information terminal acting as the rendering terminal;

decoding and playing back the encoded content by using the decoded key information; and

discarding the key information after the end of playback of the decoded content.

7. The information terminal according to claim 6, wherein the information terminal acting as the source terminal further executes, when the rights object includes information for limiting a playback count, decrementing the information for limiting the playback count every time the decoded key information is transmitted to the information terminal acting as the rendering terminal or every time playback end notification of encoded content is sent from the information terminal acting as the rendering terminal.

8. An information terminal acting as a source terminal and rendering terminal comprising:

when acting as the source terminal, the information terminal executes;

storing encoded game content and a rights object including rights information assigned to the game content and key information used to encode the game content;

establishing a secure session with a information terminal acting as the rendering terminal and generating a common key; and

encoding the key information included in the rights object corresponding to the encoded game content by the generated common key, and transmitting the encoded key information to the information terminal acting as the rendering terminal via the secure session, and

when acting as the rendering terminal, the information terminal executes;

acquiring the encoded game content;

establishing the secure session with the information terminal the acting as source terminal and generating a common key;

receiving the encoded key information transmitted from the information terminal acting as the source terminal via the secure session;

decoding the received encoded key information by using the generated common key;

decoding and executing the encoded game content by using the decoded key information; and

discarding the key information after the end of execution of the decoded game content.

9. The information terminal according to claim 8, wherein the information terminal acting as the source terminal further executes, when the rights object includes information for limiting a execution count, decrementing the information for limiting the execution count every time the decoded key information is transmitted to the information terminal acting as the rendering terminal or every time execution end notification of encoded game content is sent from the information terminal acting as the rendering terminal.

10. The information terminal according to claim 8, wherein the information terminal acting the source terminal further executes, transmitting invalid key information to the information terminal acting as the rendering terminal after execution of the encoded game content has terminated in the information terminal acting as the rendering terminal, and

the information terminal acting as the rendering terminal further executes,

receiving invalid key information transmitted from the information terminal acting as the source terminal, and

rewriting the key information used to decode the encoded game content into the received invalid key information.