Patent ID: 7958370
Filing Date: 2011-06-07
Classification: H04L

Abstract:
1. A content data management system which handles control information intended to manage decryption of content data, the system comprising: a first device that encrypts the content data to store the content data in a second device and decrypts the content data stored in the second device to reproduce the content data; and a second device that stores the content data encrypted by the first device; wherein: the first device has a host processor that inquires the first and second devices as to data transfer functions included in the devices and sets either one of a first transfer mode or a second transfer mode based on the results of the inquiries, the first transfer mode being adapted to unidirectionally transfer the control information from either one of the first and second devices to the other device, the second transfer mode being adapted to bidirectionally transfer the control information between the first and second devices; the validity of the first and second devices is mutually authenticated, and if authentication results indicate that the first and second devices are valid, key data (symmetric key data) is shared between the first and second devices; the control information is subjected to encryption processing by the first or second device using the symmetric key data and the control information that has been encrypted is transferred from either one of the first or second device to the other device in accordance with the first or second transfer mode that has been set the first device, if it has received the control information, decrypts the control information by using the symmetric key data, and decrypts the content data by using the decrypted control information, wherein, if the second transfer mode is set, during the validity authentication: