Abstract: Even if contents data distributed over a network are once destroyed, the contents data are restored, as the copyright protection is maintained. A PC memorizes backup of distributed music contents on a hard disc, at the same time as it transmits the using log information of the music contents stored in the hard disc to an EMD server. If the music contents in the hard disc are destroyed, the PC acquires the using log information from the EMD server to reproduce the backup data memorized in the hard disc depending on the using log information.

Abstract: The CPU 11 of the personal computer 1 controls the CPU 32 of the adaptor 26 made of a semiconductor IC to compute a hash value of a content-management music data base recorded in the HDD 21 and store it into the nonvolatile memory 34. When playing back a content recorded in the HDD 21, the CPU 11 computes the hash value of the music data base recorded in the HDD 21, compares it with hash values stored cumulatively in the nonvolatile memory 32, and controls the playback of the content from the HDD 21 based on the result of the comparison.

Abstract: A license server offering a content decryption key assigns leaves of a key-managed hierarchical tree structure to clients, and generates a set of node keys as a device node key for transmission to each client together with a leaf ID and a private key of the client in question. When an intermediate node of the tree structure is deemed to be the top, all nodes subordinate to the top are established as nodes related to a category defined for the top node. In this setup, a manufacturer, a content provider, or like entity managing the top node assigned the category generates uniquely an enabling key block that defines the node in question as the top, and distributes the enabling key block to devices belonging to nodes subordinate to the top node. The scheme allows the managing entity to renew the key without affecting devices belonging to any other category.

Abstract: An information processing system and method are disclosed in which information processing is performed in a highly efficient manner using an enabling key block (EKB) on the basis of a tree structure including category subtrees. A key tree is produced so as to include a plurality of subtrees that are grouped in accordance with categories and managed by category entities. An EKB is produced so as to include data produced by selecting a path in the key tree and encrypting an upper-level key in the selected path using a lower-level key in the selected path. The resultant EKB is provided to a device. If a change occurs in state of a category tree capable of processing an EKB identified in the EKB type definition list, a notification of the change in state is sent to an entity that uses the EKB thereby making it possible for an EKB requester to perform processing in accordance with a newest EKB.

Abstract: When a content is moved from a flash memory into a content database, a usage rule management program updates a variable seq-1, stored in a 0th defective block of a media defect list stored in the flash memory, to a new value seq-2. The usage rule management program calculates an MAC value (hash value) on the basis of the content stored in the data portion of the flash memory, an encrypted encryption key, and important information including the variable seq#. The usage rule management program then compares the calculated value with an MAC value stored in the header portion of the flash memory. If these two values are not equal, the usage rule management program disables reproduction of the content thereby preventing the content from being copied in an unauthorized manner.

Abstract: A cipher key is generated by first information shared in secrete between a data transmitting unit 10 and a data receiving unit 20, second information derived from duplication control information of transmit data and third information which is time change information shared between the data transmitting unit and the data receiving unit to cipher data by a CPU 12 by using the above-mentioned cipher key to transmit, from the data transmitting unit 10 to the data receiving unit 20, transmit data in which the duplication control information and the time change information are added to the ciphered data.

Abstract: The data processing system is realizable by executing a step of ciphering contents keys used for decoding ciphered contents data by applying mutually different ciphering keys before storing ciphered contents keys in memory as header data of the corresponding contents data. One of the ciphered contents keys comprises ciphered data ciphered by a ciphering key provided for by enabling key block comprising such data composition which is solely decodable by specific device by way of disposing related keys in such corresponding nodes on the path ranging from roots to leaves of a key tree structure for distributing keys. The other ciphered contents key comprises such data ciphered by a specific key proper to a corresponding storage device to enable the device for reproducing contents data to properly and selectively utilize data of ciphered key, whereby enabling the data processing system to properly reproduce decoded contents data.

Abstract: There is provided a processing apparatus which increments and thereby restores a lendable number upon receiving a content returned from a portable device, and which confirms the return of the content and increments the lendable number even when the portable device does not have or deletes the content borrowed from the processing apparatus before returning the content.

Abstract: When a player cannot play back data because a master key held by the player has a generation older than the generation of a master key having been used for recording the data, or when a recorder cannot record data because a master key held by the recorder has a generation older than the generation of a master key necessary for recording to a recording medium, the user is prompted to renew the master key for acquisition of the necessary master key, thereby enabling the data playback or data recording. The renewed master key is distributed in such a form that can be processed by a specific device via a transmission medium such as a recording medium, network, IC card, telephone line, for example, via a tree-structured distribution system.

Abstract: A cipher key is generated by first information shared in secrete between a data transmitting unit 10 and a data receiving unit 20, second information derived from duplication control information of transmit data and third information which is time change information shared between the data transmitting unit and the data receiving unit to cipher data by a CPU 12 by using the above-mentioned cipher key to transmit, from the data transmitting unit 10 to the data receiving unit 20, transmit data in which the duplication control information and the time change information are added to the ciphered data.

Abstract: An enabling key block (EKB) used in an encrypted key distributing tree structure is generated by forming a simplified 2-branch or multi-branch type tree with a terminal node or leaf which is capable of decrypting on the basis of a key corresponding to a node or a leaf of the simplified tree. Further, the EKB includes a tag for indicating a position of an encrypted key in the tree. The tag not only discriminates position but also stores data for judging the presence of encrypted key data within the EKB. As such, a considerable reduction in data quantity is realized, and the decrypting process in a device is also simplified.

Abstract: A cipher key is generated by first information shared in secrete between a data transmitting unit 10 and a data receiving unit 20, second information derived from duplication control information of transmit data and third information which is time change information shared between the data transmitting unit and the data receiving unit to cipher data by a CPU 12 by using the above-mentioned cipher key to transmit, from the data transmitting unit 10 to the data receiving unit 20, transmit data in which the duplication control information and the time change information are added to the ciphered data.

Abstract: A cipher key is generated by first information shared in secrete between a data transmitting unit 10 and a data receiving unit 20, second information derived from duplication control information of transmit data and third information which is time change information shared between the data transmitting unit and the data receiving unit to cipher data by a CPU 12 by using the above-mentioned cipher key to transmit, from the data transmitting unit 10 to the data receiving unit 20, transmit data in which the duplication control information and the time change information are added to the ciphered data.

Abstract: The invention provides an enciphering apparatus and method, a deciphering apparatus and method and an information processing apparatus and method by which illegal copying can be prevented with certainty. Data enciphered by a 1394 interface of a DVD player is transmitted to a personal computer and a magneto-optical disk apparatus through a 1394 bus. In the magneto-optical disk apparatus with which a change to a function is open to a user, the received data is deciphered by a 1394 interface. In contrast, in the personal computer with which a change to a function is open to a user, the enciphered data is deciphered using a time variable key by a 1394 interface, and a result of the decipherment is further deciphered using a session key by an application section.

Abstract: An information processing apparatus and an information processing method capable of preventing information from being copied illegally. where a hash function and a service key are stored in advance in an EEPROM of a DVD player serving as a source. In an BEPROM of a personal computer (PC) serving as a sink, on the other hand, its ID and a license key are stored beforehand. The DVD player requests the PC to transmit the ID. The DVD player then applies the hash function to data resulting from concatenation of the lID with the service key to generate a license key (=hash (ID ?service_key)). Subsequently, the DVD player generates a source side common session key and encrypts the session key by using the generated license key. Then, the DVD player transmits the encrypted source side common session key to the PC.

Abstract: A memory stores a hash value of content management data. When an IEEE1394 interface authenticates a personal computer connected thereto via a network, the IEEE1394 transmits content management data to the personal computer while receiving a hash data of the content management data from the personal computer. The IEEE1394 interface then determines whether the received hash value of the content management data matches the stored hash value of the content management data. This arrangement prevents the unauthorized copying of content data, and limits the number of uses of the content data.

Abstract: Information to be recorded is encrypted using an encryption key based on information inherent in a recording medium. The information inherent in the recording medium is specific information on a disk. When an encrypted information recorded on a recording medium is decrypted, there are reproduced from a recording medium a first file storing information encrypted by using an encryption key generated based on a random data to be inserted into a predetermined portion of the encrypted information to be recorded on a recording medium and a second file storing data indicative of a predetermined portion of the random data to be inserted into a predetermined portion of the encrypted information. The random data is detected from the encrypted information. A decryption key is generated from the detected random data. The encrypted information of the reproduced first file is decrypted using the decryption key.

Abstract: The CPU 11 of the personal computer 1 controls the CPU 32 of the adaptor 26 made of a semiconductor ID to compute a hash value of a content-managing music data base recorded in the HDD 21 and store it into the nonvolatile memory 34. When playing back a content recorded in the HDD 21, the CPU 11 computes the hash value of the music data base recorded in the HDD 21, compares it with hash values stored cumulatively in the nonvolatile memory 34, and controls the playback of the content from the HDD 21 based on the result of the comparison.

Abstract: A cipher key is generated by first information shared in secrete between a data transmitting unit 10 and a data receiving unit 20, second information derived from duplication control information of transmit data and third information which is time change information shared between the data transmitting unit and the data receiving unit to cipher data by a CPU 12 by using the above-mentioned cipher key to transmit, from the data transmitting unit 10 to the data receiving unit 20, transmit data in which the duplication control information and the time change information are added to the ciphered data.

Abstract: An information processing system and method are disclosed in which information processing is performed in a highly efficient manner using an enabling key block (EKB) on the basis of a tree structure including category subtrees. A key tree is formed so as to include a plurality of subtrees serving as category trees categorized in accordance with categories and managed by category entities. An EKB includes data produced by selecting a path in a tree and encrypting a higher-level key in the selected path using a lower-level key in the selected path. The resultant EKB is provided to a device. Distribution of EKB's is managed on the basis of an EKB type definition list representing the correspondence between an EKB type identifier and one or more identification data identifying one or more category trees that can process an EKB of an EKB type specified by the EKB type identifier.