Content transmitting device, content receiving device and content transmitting method

• US 8,225,084 B2
• Filed: 01/05/2010
• Issued: 07/17/2012
• Est. Priority Date: 06/10/2003
• Status: Expired due to Fees

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kudo, Yoshimichi, Sasamoto, Manabu, Okamoto, Hiroo
• Primary Examiner(s): Zand, Kambiz
• Assistant Examiner(s): Hailu, Teshome
• Application Number:
  US12/652,319
• Publication Number:
  US 20100106960A1
• Time in Patent Office: 924 Days
• Field of Search: 713/150
• US Class Current: 713/150
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/0869 for achieving mutual authentication cryptographic mechanisms or cryptographic arrangements for mutual authentication H04L9/3273

Abstract

Before content transmission, the content transmitting device and the content receiving device mutually authenticate each other to verify that the other device respects copyright and rightfully handles content, and then content is encrypted by shared key data and transmitted. It is arranged that in an authentication process, a time from transmission of an authentication request or a time from transmission of an authentication response until arrival of receipt acknowledgement data is measured and only when a measured time is less than a fixed upper-limit value, content is transmitted.

Claims

1. A content transmitting device comprising:

an authenticator performing an authentication with a content receiving device by transmission of authentication information and reception of acknowledgment for the authentication information, and producing and sharing an exchange key with the content receiving device;

an encryptor generating an encryption key based on the exchange key produced by the authenticator as a result of execution of an authentication process in the authenticator, and encrypting a content to be transmitted to the content receiving device, by using the encryption key; and

a timer measuring a time interval between transmission of authentication information to the content receiving device and reception of acknowledgement of authentication information,

wherein the authenticator measures the time interval between the transmission of the authentication information and the reception of the acknowledgement by using the timer, and if a measurement value of the time interval exceeds a predetermined value, the authenticator does not share the exchange key with the content receiving device to restrict transmission and/or copy of content; and

wherein the authenticator transmits the authentication information with information that indicates a number of devices the authentication information can pass through, and limits the number of devices the authentication information passes through and a range of transmission of the authentication information.

2. A content reception apparatus comprising:

an authenticator (a) performing authentication with a content transmitting device by reception of authentication information and transmission of acknowledgement for the authentication information, and (b) receiving an exchange key from the content transmitting device; and

a decryptor generating an encryption key based on the exchange key received by the authenticator as a result of execution of an authentication process in the authenticator, and decrypting a content transmitted by the content transmitting device by using the encryption key;

wherein, when the authenticator receives authentication information from the content transmitting device which does not share the exchange key with the content reception apparatus to restrict transmission and/or copy of content in the case where the time interval between the transmission of the authentication information and the reception of the acknowledgement exceeds a predetermined value, the authenticator transmits acknowledgment for the authentication information to the content transmitting device; and

wherein, the authenticator transmits the acknowledgement for the authentication information with information that indicates a number of devices the authentication information can pass through, and limits the number of devices the acknowledgement for the authentication information passes through and a range of transmission of the acknowledgement of the authentication information.

3. A content transmission apparatus comprising:

an authenticator (a) performing authentication with a content receiving device by transmission of authentication information and reception of acknowledgement for the authentication information, and (b) sharing an exchange key with the content receiving device; and

a timer measuring a time interval between transmission of authentication information to the content receiving device and reception of acknowledgement of the authentication information;

wherein, the authenticator measures the time interval between the transmission of the authentication information and the reception of the acknowledgement by using the timer, and if a measurement value of the time interval exceeds a predetermined value, the authenticator does not share the exchange key with the content receiving device to restrict transmission and/or copy of content; and

wherein the authenticator transmits the authentication information with information that indicates a number of devices the authentication information can pass through, and limits the number of devices the authentication information passes through and a range of transmission of the authentication information.

4. A content reception apparatus comprising:

an authenticator (a) performing authentication with a content transmitting device by reception of authentication information and transmission of acknowledgement for the authentication information, and (b) receiving an exchange key from the content transmitting device; and

wherein, when the authenticator receives authentication information from the content transmitting device which does not share the exchange key with the content reception apparatus to restrict transmission and/or copy of content in the case where the time interval between the transmission of the authentication information and the reception of the acknowledgement by the content transmission apparatus exceeds a predetermined time period, the authenticator transmits the acknowledgement for the authentication information to the content transmitting device; and

wherein, the authenticator transmits the acknowledgement for the authentication information with information that indicates a number of devices the authentication can pass through, and limits the number of devices the acknowledgement for the authentication information passes through and a range of transmission of the acknowledgement of the authentication information.